The Job verify infrastructure wants to record an 'instrument' and 'dataset_repo_url'. This is a requirement of ingesting into SQUASH. It's not necessary for the logic of the actual evaluation of the data. Additionally, a simple version of this information already exists in the Butler repo object.

I propose to set the default behavior so that instrument is read from the Butler repo mapper and dataset_repo_url is set to the filepath of the dataset. Users of validate_drp can set these to be other values, but we shouldn't require that all uses of validateDrp.py specify a dummy instrument and dataset_repo_url value just to run.

The spirit of this ticket is to make validateDrp.py just run and do reasonable things with the information given. If the user desires to associate additional or more specific information with the Job object, that's fine, but shouldn't be required.