Realign JGroups subsystem with the one from WildFly

The JGroups subsystem in WildFly has evolved to support forked channels and has also been including the relay support which he had grafted on.
We should rebase our own on the WildFly one, add any delta (SASL), package it to make it standalone (the WildFly one depends on a variety of clustering modules) and give it its own management model name to distinguish from the WildFly one to allow parallel installation.