Configure the encodings per-channel
Configuration of these charsets (incoming and outgoing ones) should be configurable per-room using two text entries in the configuration data-form http://xmpp.org/extensions/xep-0045.html#roomconfig of the room OR the server.
The configuration should be saved per user:
- for servers
- for channels If nothing is configured in the channel, the server values should be used, if nothing is set in the server config, the defaults should be used.
(from redmine: created on 2013-11-12)