Check in candy components for chat support

* Add candy chat system components for serving from static/
* Proptotype candy component delivery to /course/handle/chat
* Introduce JABBER_DOMAIN variable and document it in
  database_example.py
WIP: erlang cookie

WIP: working on host setting up thingie
WIP
WIP
WIP
WIP: adding (broken) clustering stuff
WIP: working on usernames being in user profile and automatic generation
of user passwords