Retrieve du data from rest api

[robertdfrench]

I need to provide some user-space reports on filesystem usage. I think I could rig something up with rbh-du to run canned queries at regular intervals and populate some intermediate database with the data I need for these reports, but it would be easier on my end if I could query this information directly from the rest api.

Does this sound like something that would make sense, or be of interest to other folks? If so, I can try to put together a PR for further discussion.