This patch makes SUBSTR() work according to ANSI rules for SUBSTRING()
function. Also, SUBSTR() can now work correctly with large INTEGER
values. The SUBSTR() syntax has not changed.

Part of #4145

@TarantoolBot document
Title: SUBSTR() function

SUBSTR() now works according to the ANSI rules for SUBSTRING().

Rules for SUBSTR() with 2 arguments:
1) let the first argument be VALUE, and the second argument be START;
2) VALUE should be STRING or VARBINARY, START should be INTEGER;
3) if any of arguments is NULL, NULL is returned;
4) let POS be MAX(START - 1, 0), END be length of the VALUE;
5) if POS >= END, the result is empty string;
6) if POS < END, the result will be substring of VALUE, starting from
   the position POS to the position END.

Rules for SUBSTR() with 3 arguments:
1) let the first argument be VALUE, the second argument be START, and
   the third argument be LENGTH;
2) VALUE should be STRING or VARBINARY, START and LENGTH should be
   INTEGERs;
3) if any of arguments is NULL, NULL is returned;
4) if LENGTH < 0, an error is thrown;
5) let POS be MAX(START - 1, 0), END be START + LENGTH - 1;
6) if POS >= END, the result is empty string;
7) if POS < END, the result will be substring of VALUE, starting from
   the position POS to the position END.

This patch is a refactoring of POSITION(). In addition, VARBINARY
arguments can now be used in this function. In addition, POSITION() now
uses ICU functions instead of self-created.

Part of #4145

This patch refactoring TRIM() and fixes an issue with incorrect trimming
of some VARBINARY values. Also, TRIM() now use ICU functions instead of
self-created.

Part of #4415

Part of #4145

Part of #4145

The CHAR_LENGTH() and CHARACTER_LENGTH() functions now use ICU functions
to determine the length of a string.

Part of #4145

@TarantoolBot document
Title: Invalid UTF-8 values and ICU

Invalid UTF-8 values may be handled differently depending on the ICU
version. For example, for this request:
```
SELECT CHAR_LENGTH(CAST(x'f0808080' AS STRING));
```

On `centos 7` with `libicu-devel-50.2-4.el7_7.x86_64` the result will
be:
```
tarantool> box.execute([[SELECT CHAR_LENGTH(CAST(x'f0808080' AS STRING));]])
---
- metadata:
  - name: COLUMN_1
    type: integer
  rows:
  - [1]
...
```

On `ubuntu 20.04` with `libicu-dev` version `66.1-2ubuntu2` the result
will be:
```
tarantool> box.execute([[SELECT CHAR_LENGTH(CAST(x'f0808080' AS STRING));]])
---
- metadata:
  - name: COLUMN_1
    type: integer
  rows:
  - [4]
...
```

Part of #4145

This patch extends the 'integration.yml' workflow and adds a new
workflow call for running tests to verify integration between tarantool
and the tarantool-php/client connector.

Part of #5265
Part of #6056
Closes #6594

This patch extends the 'integration.yml' workflow and adds a new
workflow call for running tests to verify integration between tarantool
and tarantool-python connector.

Part of #5265
Part of #6056
Closes #6584

Instead of writing to the socket fd directly using sio, we wrap it in
iostream. This will allow us to use complex communication protocols in
iproto.

One thing that should be noted about this patch is how we handle
ev_io_start when we need to wait for the socket to become readable or
writable. Since iostream_write can block because it wants to read from
the socket and iostream_read can block because it wants to write to the
socket, we might need to update input/output events before ev_io_start.
Since ev_io events can't be updated while ev_io is active, we need to
stop ev_io for this.

It's better than using ev_feed_event and ev_is_active directly.

Also, let's use EV_CUSTOM instead EV_READ/EV_WRITE for signaling,
to emphasize that this is an artificial event, which has nothing
to do with fd read/write readiness. It's okay, because input/output
callbacks don't use events at all.

It's better than using sio_socketname directly.

iproto_connection->input.fd != -1 iff state != IPROTO_CONNECTION_ALIVE.
Let's check the state instead of input.fd or output.fd, because it's
easier for understanding.

While we are at it, drop the stale comment to iproto_connection_is_idle:
the function doesn't use evio_has_fd at all.

It's not needed - we can use the iostream created in iproto
(just like a raw fd).

It's not needed - we can use the applier/relay io directly
(just like a raw fd).

Use coio_write_timeout_noxc instead.

Reading/writing fd directly doesn't let us add any data processing
transparently to the users. To overcome this limitation, let's wrap fd
in struct iostream. The new struct exposes virtual read/write methods,
which should be defined by a concrete implementation. It also allows to
access the associated fd, which is needed to poll the stream via libev.
For now, there's the only iostream implementation - plain iostream
without any processing - but we may add other implementations in future.

Apart from introducing the iostream struct, this patch also makes coio
helpers use it. From now on, coio read/write methods take iostream
instead of ev_io and create ev_io internally (in coio_wait). This is
fine, because creation of a new ev_io on stack is cheap.

Basically, this patch updates all coio users so that they call
iostream_create and iostream_close instead of coio_create and
coio_close_io. Plus, it adds a call to iostream_destroy, because in
contrast to ev_io, iostream must be destroyed explicitly.

We are going to wrap fd in iostream struct and pass it to all coio
methods. When we do that, the name 'coio' won't make any sense. Let's
switch to 'io'. We do renaming in a separate patch to reduce the blast
radius of the main patch.

Currently, we create and pass a new ev_io object wrapping the accepted
socket fd. Let's pass fd directly instead.

This is a step towards hiding all ev_io manipulations in coio internals
so that coio users don't have to deal with ev_io directly.

coio_accept uses fd from ev_io passed to it. Let's pass fd explicitly
and use coio_wait for waiting for the socket to become ready.

This is a step towards hiding all ev_io manipulations in coio internals
so that coio users don't have to deal with ev_io directly.

Drop unused coio_bind declaration while we are at it (there's no
function definition).

coio_connect sets fd in ev_io passed to it. Let's return fd explicitly
and remove the ev_io argument (we can use coio_wait, which creates a
temporary ev_io object, inside coio_connect - it's cheap).

This is a step towards hiding all ev_io manipulations in coio internals
so that coio users don't have to deal with ev_io directly.

The functions are not used anywhere. Let's drop them so that we don't
need to patch them when we switch all coio socket rw methods from ev_io
to iostream.

All it does is includes coio_buf.h, which has nothing in it but a few
inline functions.

This patch extends the 'integration.yml' workflow and adds a new
workflow call for running tests to verify integration between tarantool
and tarantool-c connector.

Part of #5265
Part of #6056
Closes #6582

tuple_bless() uses a tail call to ffi.gc() with return to the caller.
This tail call uses the current (tuple_bless) frame instead of creating
the frame for the callee (ffi.gc). When JIT tries to compile return from
`ffi.gc()` to the frame below it aborts the trace recording with the
error "NYI: return to lower frame".

This patch replaces the tail call with using additional local variable
returned to the caller right after.

Reviewed-by: Nikita Pettik <korablev@tarantool.org>
Reviewed-by: Igor Munkin <imun@tarantool.org>
Signed-off-by: Igor Munkin <imun@tarantool.org>

This patch checks out to up-to-date tarantool/checks master branch
with checking out to up-to-date tarantool/test-run master branch.
Two commits have been added to tarantool/checks. The first one is
related to submodule CI: tarantool/checks#27, the second one contains
license authors fix: tarantool/checks#28.

Add missing third party licenses to debian/copyright. Update copyright
dates for modules. Remove license entries for unused modules.

Closes #6391

This patch fixes hardening-no-pie lintian warning. Ubuntu Xenial uses
older versions of gcc which not build ELF binaries with PIE by default,
but since Xenial builds did not trigger this warning, we do not change
the behavior with additional flags.

Part of #5372, closes #6390

This patch fixes ancient-standards-version lintian warning for modern
systems. Standards-Version is 4.5.1 recommended for Debian Bullseye,
Ubuntu Groovy and Hirsute. Older versions do not support 4.5.1 and thus
yield newer-standards-version warning. This patch overrides it.

Most notable changes:

- Packages must not call /etc/init.d scripts directly even as a fallback,
  and instead must always use invoke-rc.d (which is essential and
  shouldn’t require any conditional).

- Packages may not install files in both /path and /usr/path, and must
  manage any backward-compatibility symlinks so that they don’t break
  if /path and /usr/path are the same directory.

- Packages are recommended to build reproducibly even when build paths
  and most environment variables are allowed to vary.

- Clarify that programs may invoke either /usr/bin/editor and
  /usr/bin/pager directly, or use editor and pager and rely on PATH.

- If /etc/staff-group-for-usr-local does not exist, /usr/local and all
  subdirectories created by packages should have permissions 0755 and
  be owned by root:root. If the file exists, the old permissions of 2775
  and ownership of root:staff should remain.

- Packages should not contain a non-default series file. That is, dpkg’s
  vendor-specific patch series feature should not be used for packages
  in the Debian archive.

- Binaries should be stripped using strip --strip-unneeded
  --remove-section=.comment --remove-section=.note
  (as dh_strip already does).

- Packages that include system services should include systemd service
  units to start or stop those services.

- Use of update-rc.d is required if the package includes an init script
  (previously, Policy said in one place that it was required, and
  in another said that it was recommended).

- Shared libraries must now invoke ldconfig by means of triggers,
  instead of maintscripts.

- Required targets must not write outside of the unpacked source package
  tree, except for TMPDIR, /tmp and /var/tmp.

You can read full changelog here:
https://www.debian.org/doc/debian-policy/upgrading-checklist.html

No changes was introduced in package building pipeline after upgrade
since there aren't any affecting behavior changes.

Part of #6390

This patch fixes source-contains-prebuilt-windows-binary lintian
warnings.

Part of #6390

Before this patch all PackPack-builded packages was treated as
non-maintainer updates. It fixes no-nmu-in-changelog and
source-nmu-has-incorrect-version-number lintian warnings.

Part of #6390

This patch overrides package-needs-versioned-debhelper-build-depends
lintian warning. This warning triggers when debhelper minimal required
version is less than compat level. Ubuntu Xenial repos do not contain
debhelper 10. This warning also triggers on Ubuntu Bionic and Debian
Stretch and Buster despite using debhelper 10 or newer, which highly
likely is a lintian bug. Debian Bullseye and Ubuntu newer that Bionic
pipelines do not yield this warning.

Part of #6390

This patch overrides embedded-library lintian errors
for curl and libyaml.

Part of #6390

This patch fixes malformed-override lintian warning.

Part of #6390

This patch fixes duplicate-globbing-patterns lintian warning.

Part of #6390

This patch extends the 'integration.yml' workflow and adds a new
workflow call for running tests to verify integration between tarantool
and the mysql module.

Part of #5265
Part of #6056
Closes #6577

Part of #6356

@TarantoolBot document
Title: Literals for INTEGER, DECIMAL and DOUBLE

The rules for parsing numeric values have changed:
1) a value consisting of digits without decimal point and exponent will
be parsed as INTEGER;
2) a value consisting of digits and a decimal point will be parsed as
DECIMAL;
3) a value consisting of digits, containing an exponent and possibly
containing a decimal point, will be parsed as DOUBLE.