Feature #18765: rbd-mirror: add support for active/active daemon instances
rbd-mirror A/A: separate ImageReplayer handling from Replayer
Create a new interface (i.e. InstanceReplayerInterface) that have API methods for acquire and releasing images by global image id. The logic from Replayer that handles creating, starting, and stopping ImageReplayer instances should be moved to a new InstanceReplayer class.