Add capability to stage ("restore") files ("objects") in an S3 bucket for transfer

[jeff-cohere]

I found this when messing around with an S3 client to fetch PlanetMicrobe data via our iRODS-S3 proxy. Seems to be identical in structure to the file staging operations the DTS already deals with. We should add this capability to our S3 endpoint.

It looks like the RestoreStatus field is an "optional" object attribute that can be requested specifically by e.g. list_objects_v2 as described here (search for RestoreStatus).