workflows: Holding Pen JS update

• NEW Adds new buttons to the Holding Pen details pages to delete and restart current task.

• Adds common JS functionality across Holding Pen in a new flight component.

• Reworks the JSON responses given to common ajax calls to map to bootstrap alerts and wrap exceptions.

• Updates "use strict" statements to be within function scope as recommended by jshint.

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