The JSON serializer for our API uses ``json.loads``, which permits *any*
valid JSON (including bare integers, boolean values, etc). Lots of our
code, however, assumes that inbound JSON content will be a dict.
see: #4756
* Remove fields from browsable API raw data that are set implicitly based on URL / parent object.
* Fix issue where a group/host could be assigned to a different inventory.
* Update validation to load values from existing instance if not present in new data; allows PATCH requests to succeed.
* Remove job_args, job_cwd, job_env, result_stdout and result_traceback fields from job listings.
