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>