OO-449: remove all surviving @Transactional, add unit tests in groups to test them, add a missing view in IM, add unit tests to check it...

OO-449: first part of the implementation: remove smack libraries, refactor controller and unify them, implements messaging across the OpenOLAT event bus, implements administration part to enable chat...

OO-120: reduce the dependency graph of our chat implementation by removing somme inner class, remove the groupchatcontroller after destroy, update smack to 3.2.2