Cluster refactoring

[BorysTheDev]

Problem: we have a lot of methods that use a vector of migrations and because migrations can be removed we need to lock mutex in all these methods
Solution: make the vector of migrations unchangeable. We already consider the slot migration process as part of the config, so we can use absolutely the same approach, as we use for config, for the vector of migrations and store it in the config or create a thread_local ptr for it. In this case, we don't need any synchronization to operate with migrations and use mutex only in the case when the config is updated (during DFLYCLUSTER CONFIG command and migration finalization).

Other improvements:

1. make the interface of incoming and outgoing migration more similar or even make an ancestor
2. make flush slots in one place for all migrations and config, during DFLYCLUSTER CONFIG command
3. instead of migration_mu_ we can use set_config_mu_ without any issues.
4. update streamer
5. refactor DflyClusterGetSlotInfo do simple atomic::add(relaxed) instead of a mutex
6. remove unused code:

• auto host_ip = cntx->conn()->RemoteEndpointAddress();
• #include

8. need to rewrite SlotRanges::Merge() because it is slow and call under mutex
9. move tl_cluster_config out of cluster_family into cluster_config