OO-615: implements a simple filter to allow CORS (cross origin resource sharing) but restricted to the rest api

OO-609: if the evaluation raise an error, denied access instead of red screen and log the condition, it's not the fault of the user

OO-606: don't return "WWW-Autorization" if authenticated, doesn't allow BitKinex in OLATServlet, update cache config converter...

OO-449: show "do not disturb" status in the homepage, list of course members, list of groups members

OO-591: implement sort by role in the different list of groups, add missing i18n key in "User mamangement" and fix the role renderer there

OO-588: fix an issue where the last course building block's resource is not imported with the rest of the course

OO-584 fix nullifying of group title and description in project broker (Patch from Stephan Clemenz, VCRP)