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
I'm unsure why this needs to be here. Shouldn't `initialize_fields` (https://github.com/projecthydra/sufia/blob/master/sufia-models/app/models/concerns/sufia/generic_file/web_form.rb#L17-L22)  take care of it?  Then this form would look very much like it's counterpart for generic_file: https://github.com/projecthydra/sufia/blob/master/sufia-models/app/models/concerns/sufia/generic_file/web_form.rb#L17-L22