Add jgroups based HA

[daviddawson]

Option to enable a jgroups based ckustering. When enabled, each node should be able to receive event. When a node receives an event via the external APIs, it should persist the event, then send it over jgroups, and pass it to its internal subscribers. Other nodes will then receive it, and pass it in to their stream processing/ subscribers, but not attempt to persist it. See https://github.com/daviddawson/jgroup-message-cluster/blob/master/src/main/java/io/JGroupsMessage.java