Backend: Run checks

[Topvennie]

Tasks

Beta Give feedback

1. Run extra checks after structure checks
2. Only give student access to logs files when they're allowed
3. Give teachers ability to trigger a memory or timeout limit error
4. Zip submissions
5. Figure out volume situation
6. Enforce memory limit and time limit
7. Run structure checks
8. Write some tests
9. Fixtures
10. Access submission files and logs

[Topvennie]

Enforce memory limit and time limit: 486c87f
Give teachers ability to trigger a memory or timeout limit error: 05820e7
Run extra checks after structure checks: cdee99f
Zip submissions: cdee99f
Run structure checks: cdee99f
Fixtures: eafebd5
Figure out volume situation: 170d038
Only give students access to log files when they're allowed: 8b93c44
Access submission files and logs: 3cffe58
Write some tests: 4906730