Pre-open an exam to open an exam immediately

Revert Old feature: make generation and starting exams independent again

When starting exams, previously all random exams were generated before the actual exam could be started. This gave all students the time to already connect to the system, solve any issue and then start all together on the exam. Today, when clicking on “start”, it took several minutes to create all 60+ exams, then every student had to connect, show their id, etc. and we ran into several issues such as wrongly set times on two computers, camera issues etc.

It will be nice if the old functionality comes back.