access: Holding Pen role addition

* Add "holdingpenusers" role.

* Fixes PEP8 issues in local_config.py.

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

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