EZP-21548 : clear role assignments cache when dealing with locations

As UserService relies on LocationService to assign/unassign groups to users, we must find a way to invalidate role assignments cache when creating, deleting, moving, hiding or revealing locations.

I followed @andrerom's recommendations on JIRA but I feel like clearing all role assignments cache on every location operation may be a bit too much. Should I load the location data to restrict cache clearing to contentId ? And if so, how do I load this data from this service ?