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>

Georgy Moshkin authored 2 years ago and Yaroslav Dynnikov committed 1 year ago

This patch includes:

- Tarantool stored procedure `proc_cas`.
- Lua API `pico.cas`.
- Integration tests.

Now the function returns `first_index` instead of the number of entries
deleted - it has no practical purpose.

This patch adds a missing test for `pico.raft_compact_log` Lua API.
Also, it changes the API to be more alike other relevant Lua functions:
`raft_propose_*`, `raft_read_index`, `raft_timeout_now`.

refactor: rename UpdateInstanceRequest -> update_instance::Request, UpdateInstanceResponse -> update_instance::Response

Use direct structure names instead of aliases for better IDE code surfing