KAZOO-1539: started work on listener_federator
KAZOO-1539: finalize listener_federator and update wh_nodes as well as ecallmgr_registrar to support it
KAZOO-1539: federate channel lookups/status requests
KAZOO-1539: start federating conference search requests
KAZOO-1539: collect registrations from the cluster and federate wh_hooks_listener