add supplement to socket-bindings in template assembly

The messaging.xml subsystem configuration defines a "ha" supplement used to build the standalone-full-ha.xml.

This supplement requires to have a socket-binding for multicast:

   <socket-binding name="messaging-group" port="0" multicast-address="${jboss.messaging.group.address:231.7.7.7}" multicast-port="${jboss.messaging.group.port:9876}"/>

However, this socket-binding is always added even when the "ha" supplement is not used.
We end up with a standalone-full.xml configuration with the regular messaging subsystem (no ha parts) and the messaging-group socket binding.

Ideally, this socket-binding should only be added when the ha supplement is used.
One way to achieve this would be to allow <socket-binding> definitions inside the <supplement>/<replacement> elements.