Removing delete-by-fileset logic from Blitz deleteObjects()

We no longer delete a whole fileset at a time. Delete images as before and let the server
handle cleanup of filesets as necessary.
UI for partial MIF delete. Needs fs-Ids from server
Blitz FilesetWrapper.listFiles() gets Original Files
Delete MIF 'error' message
Delete error UI more similar to chgrp UI
Use 'muliti-image Fileset' in UI
Handle delete MIF fs_Id from server
Merge pull request #1143 from will-moore/delete_MIF_handling_10806

Delete mif handling 10806