[Jingle] XEP-0176 - how to find STUN/TURN servers

[Justin Karneges]

Section 9 mentions STUN/TURN, but does not suggest how a client may discover 
these services through the XMPP server.  In particular, TURN servers may 
require credentials and the client will need to know what they are.

Even XEP-0065 has a way to locate a relay service, through disco.  I think we 
need a similar approach in XEP-0176 before we can consider it ready.

-Justin