add an option to create replicated tables within replicated db without specifying zk path and replica id
add replicated sch pool
disable replication of alter queries for replicated tables in replicated dbs
snapshot prototype. amend of replicated db workflow
add prototype of integration tests for replicated db
* "lock_acquire_timeout" controls for how long a query will continue to
acquire each lock on its argument tables
* "lock_acquire_timeout_for_background_operations" is a per-table
setting for storages of *MergeTree family
