When restoring a backup containing a question bank, we were always
trying to match questions to an existing category on the target course
if once existed. This meant that when duplicating a qbank on the same
course, or importing the same qbank to another course multiple times,
only one of the restored qbanks would end up with questions in it.
This adds a mechanism to record any activities in the backup which
support `FEATURE_PUBLISHES_QUESTIONS`. Then when we restore the
questions, we check if we will be restoring the original activity they
belong to, and skip trying to match them to an existing category. This
means a new copy of each question will be created, and moved to the new
copy of the qbank once it is created.
Mark Johnson
2785d6f2bd