Implementation notes for GetFileIDs functionality
In the SBPillar implementation a GetFileIDsRequest is considered a success in all cases unless an error occurs at the backend.
In the case that a list of fileIDs are supplied the intersection of the files in the pillars store and the list of files are returned with the response.
This means that even if one requests the listing of files that is not on store the request is considered a success. Also a successful handled GetFileIDsRequest can provide a response with an empty list.