deposit: exposure of handle_field_msg

* Assings event connection to handle_field_msg to make it available
  externally.

Signed-off-by: Kamil Neczaj <kamil.neczaj@cern.ch>
Reviewed-by: Javier Martin Montull <javier.martin.montull@cern.ch>
mixer: fix requirements

Signed-off-by: Esteban J. G. Gabancho <esteban.gabancho@gmail.com>
legacy: fix webbasket template translation string

* Fixes Babel gettext string replacement.  (closes #2362)

Signed-off-by: Jiri Kuncar <jiri.kuncar@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>
access: Holding Pen role

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

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