Implement blueprint: 'feature-feeder-in-core'.

Missed inotify even in the replicaor handler process was foxed.
replicaor_init was splited on two function:
  - replicaor_prefork -- create replicaor spawner process;
  - replicaor_init -- initialize replicaor fibers in the main tarantool
	                  process.

Test and test configuration files in box_replication soute was
clenupped and updated.