Add cluster support to Jentrata / Hermes

When running Hermes in a cluster configuration, running multiple
instances of Hermes behind a load balancer, there are problems with
handling the acknowledgement messages from outside the cluster.

In more detail, whenever a message is sent from a cluster of Hermes
instances the receiving ebMS will reply with an acknowledgement (when
set). Since the sending hermes instance is part of a cluster behind a
loadbalancer the acknowledgement will be received by the loadbalancer
and will be forwarded to one of the Hermes instances behind it. If this
is the original, sending, Hermes instance all is well. However when its
not, the receiving Hermes instance will reply with an error. And the
original sending Hermes instance will start resending the original
message.

With the code supplied the receiving Hermes instance will first try to
find the originating order message in its own database. However when it
can't find it, it will identify the original, sending, Hermes instance
based upon the RefToMessageId and will forward the acknowledgement
information to the identified Hermes instance. The indentified Hermes
instance will process the information as if it received the
acknowledgement and will return a reply to the receiving Hermes
instance. The receiving Hermes instance will process the reply and will
reply to the ebMS which sent the acknowledgement.