Jabber: implement SCRAM-SHA-1-PLUS auth

[dartraiden]

The "-PLUS" suffix is used only when the server supports channel
   binding to the external channel.  If the server supports channel
   binding, it will advertise both the "bare" and "plus" versions of
   whatever mechanisms it supports (e.g., if the server supports only
   SCRAM with SHA-1, then it will advertise support for both SCRAM-SHA-1
   and SCRAM-SHA-1-PLUS).  If the server does not support channel
   binding, then it will advertise only the "bare" version of the
   mechanism (e.g., only SCRAM-SHA-1).  The "-PLUS" exists to allow
   negotiation of the use of channel binding.

https://tools.ietf.org/html/rfc5802

[GitHubbie0836]

Не работает
https://forum.ru-board.com/topic.cgi?forum=5&topic=50156&start=1000#6

[GitHubbie0836]

Не работает:
Proposed channel binding type isn't supported.