registry: (auto)discovery and proxy fixes
sqlalchemy: use of autodiscover registry proxy
comments: modal dialog fix

* Actually removes modal elements on modal close, not just hides them, resulting
in duplication.

Signed-off-by: Adrian-Tudor Panescu <adrian.tudor.panescu@cern.ch>
registry: namespace fix

Co-authored-by: Jiri Kuncar <jiri.kuncar@cern.ch>
legacy: import fixes
legacy: import and gettext fixes
workflows: moves remaining files

* Moves old BibWorkflow files to new workflows module.

* Updates imports in deposit module.
workflows: updates javascript

* Several updates to the templates and JS files in the
  workflows and holdingen views to conform better with
  standards and to fix some issues.

* Fixes a bad import in Holding Pen view.
workflows: add simple testsuite