workflows: Holding Pen update

• Removes some uninteresting/unused columns in the Holding Pen main table and adds a new columns called categories containing any record subjects found, if applicable.

• Cleans some blueprint code and routes in Holding Pen.

• Refactors the tag system used in the main Holding Pen display. Now using a new JS package called bootstrap-tagsinput.

• Changes approval widget design and layout.

• Improves detailed display of workflow definition.

• Updates in harvesting workflow tasks.

• Adds a new template for detailed layout.

• Fixes a problem with hotkeys in the main table display.

• Adds a new bootstrap-tagsinput package for use in the Holding Pen display.

• Removes the current config.py and moves the enumerations into engine.py and models.py where appropriate and changing the naming from CFG_OBJECT_VERSION to ObjectVersion.

• Updates deposit models to use the new ObjectVersion.

• Removes the DATA_TYPE enumeration. This will now be dynamically loaded from the database in the holding pen.

• Initial implementation of a new Edit Record widget which will be used for (limited) record editing from Holding Pen. Still WIP.

• Adds templating blocks for Holding Pen navigation bar and record preview.

• Creates a new field rendering macro for better WTForm rendering.

Co-authored-by: Jan Aage Lavik <jan.age.lavik@cern.ch>