workflows: actions JS loading

* Makes the JavaScript assets loading for actions separated from
  the general assets loading to allow for easier additions of
  actions on overlays.

Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
workflows: documentation enrichment

* Enriches the documentation of the Workflows module by adding
  more information on actions and the Holding Pen.

Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
workflows: task_counter value check

* Checks if the task_counter parameter is a list when saving
  an BibWorkflowObject. It is required to avoid a problem with the
  underlying workflow engine.

Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
workflows: Holding Pen details fix

* Fixes a problem where the detailed page for Holding Pen
  object caused an exception when information on next/previous
  objects from the table were missing.

Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
access: fix PEP8 and PEP257 for models

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
access: new has_(super)_admin_role methods

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
access: Flask-Admin interface addition

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
legacy: webuser usage cleanup

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>