Current commit introduces distributed SQL in picodata (we use
'sbroad' library). Now it is possible to execute cluster-wide
SQL with 'pico.sql([[query]], {params})' lua method.

Current limitations:
1. DDL is still not implemented in picodata, so space sharding
   is mocked by '_pico_space' space (we'll remove it later).
2. We still have duplicating symbols of the Tarantool module in
   sbroad and in picodata rlibs.
3. We need to reuse piocdata's sharding functions and handle the
   case when different spaces in the query have different sharding
   functions.

Co-authored-by: Georgy Moshkin <gmoshkin@picodata.io>

* _picodata_index keys now include space_id
* _picodata_space distribution type changed to "array"
* _picodata_space format type changed to "array"
* add Spaces::insert and Indexes::insert methods
* Ddl now has #[serde(tag = "kind", rename_all = "snake_case")]
* Dml now has #[serde(tag = "op_kind", rename_all = "snake_case")]
* Distribution now has #[serde(tag = "kind", rename_all = "snake_case")]

The main focus is on the snapshot recovery scenarios (bootstrap /
cathcup) interleaving with explicit CaS operations, rather than on
leadership changes and joins.

Refactor corresponding tests accordingly

Yaroslav Dynnikov authored 1 year ago and Yaroslav Dynnikov committed 1 year ago

Adopted styleguide is "actual == expected", not vice versa.

Integration tests use some TCP ports. These ports may conflict with:
- already running instances on the developer host
- any other program on the developer host or on the CI host

The `port_range` fixture checks that all ports between
base_port and max_port (inclusive) are unused,
so integration tests are allowed to run.

This reverts commit 267dc61b.

It produces false-positive errors in CI.

It also provides better experience with various IDEs.

Also remove the unnecessary `start_new_session` flag from explel
function.