Automatic exam addmission

[tynsh]

There needs to be a way to automatically admit students to final exams. Currently each student has to be checked manually.

[tynsh]

There is an endpoint making this possible, but this has to be integrated better. The blocker is, that some sort of queuing system needs to be used. I've looked at RQ and rq-scheduler, which seem a good fit, since we need redis anyway.