Make replication queue implementation pluggable

We needed to make the ReplicationQueue listenable. We needed events for adding a command to and flushing the queue.

org.infinispan.factories.EmptyConstructorNamedCacheFactory

Just added ReplicationQueueNotifier.class to the @DefaultFactoryFor annotation.

org.infinispan.notifications.replicationqueuelistener.ReplicationQueueNotifier

Interface for the ReplicationQueue notifier.

org.infinispan.notifications.replicationqueuelistener.ReplicationQueueNotifierImpl

The ReplicationQueue notifier implementation. Supports events for adding and a command to and flushing the queue.

org.infinispan.notifications.replicationqueuelistener.annotation.Flush
org.infinispan.notifications.replicationqueuelistener.annotation.ReplicableCommandAdded

The bare annotations to add to ReplicationQueue listeners.

org.infinispan.notifications.replicationqueuelistener.event.Event

The interface for the command added and flush event implementations.

org.infinispan.notifications.replicationqueuelistener.event.FlushEvent
org.infinispan.notifications.replicationqueuelistener.event.ReplicableCommandAddedEvent

The event implementations.

org.infinispan.remoting.ReplicationQueue

Updated to implement listenable.
Throws the command added event AFTER it has been added to the queue. It includes the size of the queue AFTER the command has been added.
Throws the flush event AFTER the queue has been flushed. It includes the size of the queue to be flushed.