Support reloading AMQP broker federation configuration

Add support for reload of AMQP federation broker connection configuration from XML and broker properties such that active federations are stopped and updated with new configuration settings, and support add and remove of AMQP federation broker connections.

This change will explicitly not reload broker connections that contain Mirror configuration as that is not supported and could lead to breakages of mirroring.  Mirrors can be added if not present before but once added they cannot be removed without a broker stop and restart.