Replication refactor part 6 (#1484)

Single (instance level) connection to a replica (messages from all databases get multiplexed through it)
ReplicationClient split in two: ReplicationClient and ReplicationStorageClient
New ReplicationClient, moved under replication, handles the raw connection, owned by MainRoleData
ReplicationStorageClient handles the storage <-> replica state machine and holds to a stream
Removed epoch and storage from *Clients
rpc::Stream proactively aborts on error and sets itself to a defunct state
Removed HandleRpcFailure, instead we simply log the error and let the FrequentCheck handle re-connection
replica_state is now a synced variable
ReplicaStorageClient state machine bugfixes
Single FrequentCheck that goes through DBMS
Moved ReplicationState under DbmsHandler
Moved some replication startup logic under the DbmsHandler's constructor
Removed InMemoryReplicationClient
CreateReplicationClient has been removed from Storage
Simplified GetRecoverySteps and made safer

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Co-authored-by: Gareth Lloyd <gareth.lloyd@memgraph.io>

src/dbms/database.cpp

@@ -21,7 +21,7 @@ template struct memgraph::utils::Gatekeeper<memgraph::dbms::Database>;
 
 namespace memgraph::dbms {
 
-Database::Database(storage::Config config, const replication::ReplicationState &repl_state)
+Database::Database(storage::Config config, replication::ReplicationState &repl_state)
     : trigger_store_(config.durability.storage_directory / "triggers"),
       streams_{config.durability.storage_directory / "streams"},
       plan_cache_{FLAGS_query_plan_cache_max_size},