Implement REPLICATED mode as a degenerated DISTRIBUTED mode (nowOwners>=clusterSize)

This has already been done in the case of state transfer, where the distribution state transfer code is reused for replicated caches as well.

The main reason behind this improvement is to simplify/reduce the code. Also there will be some additional benefits:

• ATM in replicated mode, the JGroups coordinator always plays the role of main lock owner. The coordinator might get overwhelmed as it has to process the additional TxCompletionNotificationCommand on every transaction (direct consequence of being main lock owner). OTOH in distributed mode, the lock owner is spread between the cluster members.

As an optimisation, on REPL mode, we can use multicasting (when on UDP) for message sending.