workflows: Holding Pen authorization

* Adds decorators for permission check to Holding Pen blueprints.

* Adds new ACL with basic "viewholdingpen" authorization to access
  the Holding Pen.

Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
access: Holding Pen role

* Adds Holding Pen role and authorization linked to the
  viewholdingpen action in workflows module.

Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>