KAZOO-696: support nightmare transfer requests for channel info

This works with an earlier change to FreeSWITCH.  During nightmare transfer I have patched FreeSWITCH to issue a fetch request for channel information.  Based on the result FreeSWITCH will then attempt to bridge to the server with the call.

Notice:
- This requires the media server hostname to be resolvable by each FreeSWITCH server
- The ACLs should allow traffic from any FreeSWITCH server