WIP: Job Files API.
Update LWR client through LWR changeset 51f097d.

Add RemoteTransferAction - to allow LWR server to stage files up and down by downloading/uploading them. Still need to augment Galaxy to support such an endpoint for job-related files.
Extend SecurityHelper to allow generation of different "kind"s of keys.

There has been talk about including the object's class into the hash when generating keys so the ids are not overlapping between model types. This change could allow that, but my immediate desire is to just to create single-purpose per job keys to allow external job running code to access files on behalf of a given job.
Rebase into job files API.