Clean BaseController

remove unused functions

_get_user(self, reference):
_get_pkg(self, reference):
_get_group(self, reference):
_get_tag(self, reference):
_get_request_data(cls, try_url_params=False):
_make_unicode(cls, entity):
_get_timing_cache_path(self):
_handle_update_of_authz(self, domain_object):
_prepare_authz_info_for_render(self, user_object_roles):