[REFACTOR] moved MUC component to Saros Core

Removed the getTitle() method and implemented it into the
ChatRoomCompsite instead.

Change-Id: I48a8edcd8fcff2ea84353f7b8b3a24e41b895680
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1441
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>