[INTERNAL] removed SessionManager from all CollaborationUtils methods

It only pollutes the code because the SessionManager have to be injected
into every component that calls those methods. The CollaborationUtils
will now do the proper injection.

Change-Id: I2f24aa4bff1871a7363f03eb9f8d7b0e665a93c7
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1169
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>