Support WorkerRun on Element
- add
worker_run_idFK onElement(nullable, blank) - make it available in the admin details of an Element, using
raw_id_field - expose it in
CreateElementsendpoint (required for UFCN) - bonus: expose it in
CreateElementendpoint
Rules for endpoints:
- we only support
worker_version_idXORworker_run_id, raise a 400 if both are supplied - the endpoint must load the
WorkerRunfrom its ID to check its existence - and use the related
WorkerVersionasworker_version_idon the resulting elements (so we end up with both worker_version & worker_run being set on the Element)