OO-291: implements public flag for members in group configuration, check paypal against waiting list, test reservations, fix missing chat checkbox in group collaboration tools configuration

no-jira: remove a setLastUsage test for the RepositoryManager which is fully random and doesn't test anything

OO-291: avoid groups and areas with the same name if a course is exported with the backward compatibility flag

OO-323 removed mime-type accept limitation on file upload, does not work stable enough. Checked on server side after upload anyway.

OO-291: implements the rules to show the course tab, areas and rights in group's edit controller, rework the areas tab