CMS-1813: Convert relationshipType_list to use value objects

CMS-1812: Convert relationshipType_get to use value objects
CMS-1816: Convert relationshipType_update (relationshipType_createOrUpdate) to use value objects
CMS-1815: Convert relationshipType_create (relationshipType_createOrUpdate) to use value objects
CMS-1814: Convert relationshipType_delete to use value objects