More specific ability to list-files

[aulneau]

I've started playing around with the different scopes for putFile stuff such as putFileArchival. In this use-case it would be very helpful for some kind of API like listFiles(path_to_this_file/file)` in order to get all of the older versions of that specific file. I'd prefer not to list over all of the various files in the hub to find just that specific one.

Additionally, for sharing of files, I don't see a way to be able to provide a gaia hub config to this method to allow other users to search if they have a scoped token. I also don't want to expose the entire contents of a hub to a user with a scoped token.