Create and manage exam projects from courses

[math-sl]

When we use "assignments" for exams, in certain situations we don't want the exam material to be available as soon as a student finish the examen and leave the room.

Since the backup system does keep exams documents available, the only way to make them unavailable is to create a new project for the exam and remove the student from the project after.

The request is to have a way to automate a specific exam project creation and student access management from the course page. We could create the project in advance and add and remove student from the project. Ideally, downloading files from exam projects should not be possible. The exam project would need to have the same settings (and licence) as the main course student's projects.

Possible addition to the course page:

From the assignment page, there would be a new "Add exam" button, which create a new exam project.

An "assign exam" button would work similarly to the current assign button: copy files from a folder to the exam project and add student to the project.

A collect exam button would work similarly to the collect assignment button, copying exam material to the teacher project's for grading and removing the student's access to the exam project.

The return exam button would move back graded material and give back student access to the project.

Related: #7882