new compat option: 'compat.replication_synchro_timeout'

Dev. issue: https://github.com/tarantool/tarantool/issues/7486

Product: Tarantool
Since: 3.3.0
Root document:

• new page https://www.tarantool.io/en/doc/latest/reference/reference_lua/compat/replication_synchro_timeout/
• check pages in https://www.tarantool.io/en/doc/latest/platform/replication/ for behavior description

SME: @ Astronomax

Details

The compat module allows you to choose between:

• the old behavior: unconfirmed synchronous transactions are rolled back
  after a replication.synchro_timeout.
• and the new behavior: A synchronous transaction can remain in the synchro
  queue indefinitely until it reaches a quorum of confirmations.
  replication.synchro_timeout is used only to wait confirmation
  in promote/demote and gc-checkpointing. If some transaction in limbo
  did not have time to commit within replication_synchro_timeout,
  the corresponding operation: promote/demote or gc-checkpointing
  can be aborted automatically.
  Requested by @Astronomax in https://github.com/tarantool/tarantool/commit/f0f9647d8b80a2bad56b9462fff28b28af2203aa.

Start with the new compat.replication_synchro_timeout page linked in the issue and compare its structure with nearby compat reference pages. Read the replication documentation linked in the issue to verify the old and new transaction behavior, then document the option, its version, and its effects on promote, demote, and gc-checkpointing.