Output vizualizer

[vmcj]

I tried to implement https://github.com/DOMjudge/domjudge/issues/367. This is still a bit rough but I rather first get some feedback instead of continuing with this if this is not what @eldering envisioned.

The main problem I currently have is which testcases to visualize, do we only want the failing one and if so only the wrong-answer one or do we just want to try all of them and accept that the script might fail as the team output might not conform to the expected output. (For example: the team might have stopped halfway through the problem or might still have debug output etc.)

The visualized team output for boolfind is ofcourse not very helpful but as this is only a demo this is the best for now.

When implementing this I found out we could just always visualize as a task with lower priority and update the visualization task with the judgehost which should have the needed files. I wrongly assume that the file will always be at the judgehost to keep this simple but that should still be fixed if we want to continue with this.