support for same transaction touching multiple nodes (multiple VMs)

E.g. if a distributed transaction managers touches two embedded Infinispan nodes within the same transaction.
Could be implemented using the Hot Rod client approach - but in an embedded fashion!
EmbeddedClient <-- implements logic above
Except comms are in-VM for local entries
And via RpcDispatcher for remote entries
RemoteClient extends EmbeddedClient
Adds proper HotRod layer for comms
Including failover, smart routing, etc.