Deleted replica applies its own deletion from the `_cluster` space

Related dev. issue(s): https://github.com/tarantool/tarantool/issues/10088

Product: Tarantool
Since: 3.2
Root document:

• https://www.tarantool.io/en/doc/latest/concepts/replication/repl_sync/
• https://www.tarantool.io/en/doc/latest/how-to/replication/repl_bootstrap_auto/#adding-and-removing-instances
• https://www.tarantool.io/en/doc/latest/reference/configuration/configuration_reference/#configuration-reference-replication-synchro-quorum

SME: @ CuriousGeorgiy

Details

The deleted replica will now apply its own deletion from the _cluster
space. This will allow to delete a node regardless of
the current configuration in case the _cluster space is synchronous. The
deleted replica will need to be resubscribed, and if it is restarted
before resubscription, it needs to be started as an anonymous replica.

However, if a replica is down, then it will still be impossible to remove
it from a 2-member cluster without manual lowering of the
replication_synchro_quorum option. In such a scenario the instance should
not be turned off before it is dropped from the _cluster space when
synchronous replication is enabled for the _cluster space.
Requested by @ CuriousGeorgiy in https://github.com/tarantool/tarantool/commit/25aac111ce10bab38f5e43f72c2d5d322a1e0065.

Start with the replication synchronization guide and the “Adding and removing instances” section, then review the replication_synchro_quorum configuration reference. Update the documentation to cover deletion from the synchronous _cluster space, resubscription or anonymous restart requirements, and the two-member-cluster caveat when a replica is down.】【。