privacy(call): use content addressing to help prevent call id leakage through protocol

[Zaba505]

Currently, the call id is used for specifying the protocol nodes communicate with it. This leaks the call id via the libp2p protocol negotiation which then opens an unnecessary attack vector for bad actors to take advantage of. A potential solution is to mandate a password for each call for encrypting each call id, as well as, using a non-unique protocol for at minimum chat messages.

See #25 for discussion about a non-unique vs unique protocol