Add plagiarism detection for evaluations

[jorg-vr]

This pull request adds detect plagiarism buttons to activities in an evaluation. These generate a plagiarism report using the submissions selected for the evaluation.

I also updated the design a bit.

• 'Evaluate' has become an outline button instead of an icon caret. This makes it much more discoverable for new users and it deserves to be seen as it is probably the primary action.
• As there are two buttons now, I gave the exercise table full page width. The help text has been moved to an expandable details block at the top

• Documentation update can be found at dodona-edu/dodona-edu.github.io#

Closes #5528, #2503 and #3457

[chvp]

Maybe this was discussed in the initial PR, but I don't particularly like the wording "Plagiaat controleren". As far as I understand it, Dolos can never say with certainty plagiarism occurred, only whether certain submissions are similar to others.

[jorg-vr]

This has not been discussed before. But I am not sure about the alternative.

I think the button should clearly state the intent of the action, which is detecting plagiarism.
More detailed information about what to do with the info, and witch caveats to take into account should be listed in Dolos.

But I am open to changing the button text if you have a good alternative suggestion