plugin XEP-0353: Jingle Message Initiation implementation: This plugin uses the new `XEP-0166_initiate` trigger to initiate a Jingle session with messages if the peer jid has no resource specified. On reception, if the sender is not in our roster, a confirmation is requested to user to avoid leaking presence and IP. If user refuses the session for somebody not in roster, nothing is sent at all (the request is just ignored).