OO-3332: the main calendar is always visible in its context (course calendar always visible in its course, same for group, user and home)

OO-3330: per default save the calendar setting with 'visible' and 'aggregated' like the defaults if there are no user configuration yet

OO-3323: Pool manager and pool owner should be able to remove question from pool, pool manager and group member should be able to remove question from group

OO-3317: break the spring dependency cycle to ensue the access control module set the settings on the database once initialized

OO-3312: hide the lost+found in the document pool site, exclude competence gained from a taxonomy level with the identifier lost+found or orphan-fach (inclusive parent line) to access the document pool site