Adds full metadata editing for Collections (same DC fields as GenericFiles)

Fixes hydra-editor style partials in views/records.

refs gwu-libraries/gw-sufia#82
refs gwu-libraries/gw-sufia#25
The form for editing metadata on a GenericFile didn't match the form for editing the same metadata fields on a Collection because one was using form_for and the other was using bootstrap_form_for.  I made them consistent, going with the standard rails form_for, since it's more common and the GF form (which used regular form_for helper) obviously has had more attention over the life of Sufia.