Check unused questions

[moleculech]

Summary

Motivation

As editing teacher,
I would like to see if there are any questions in the question bank that are not used in any of the tests in this course.
In order to be sure that no old or unused questions are in the course.

Appendix

• Show list with unused questions in the check result page
•  The check fail if more than x questions are not used in the check result page.
• Add a setting to trigger the failure after x unused questions.
• The result links to a question bank: /question/edit.php?courseid=xxxx