No options to remove students from deactivated examiner

[torgeirl]

If an examiner is deactivated on a semester, they can no longer be managed as examiners on the semester's assignments. This is an issue if the examiner already have been assigned students on upcoming assignments.

Workaround

1. Reactivate the examiner
2. Remove students from them on each upcoming assignment
3. Deactivate the examiner again

Suggested solution
No longer hide deactivated examiners from manage examiners. Instead add a visual indication that they are deactivated (similar to their student counterpart on assignments) and only allow removing students from them (prevent adding new students).