[entity] Entity.related(): add a targettypes argument (closes #2957313) This allows to restrict the entity types returned by the method (passed to cw_related_rql). When such an argument is given, no caching happens.

option_group_changed('port', 'main', 'web')
option_group_changed('query-log-file', 'main', 'web')
option_group_changed('profile', 'main', 'web')
option_group_changed('max-post-length', 'main', 'web')