Better urls in the task archive

[Kostero]

I'd like to be able to have a direct link to problems in task archive, e.g. https://szkopul.edu.pl/task_archive/oi/24/e1/fla should link to the problem fla from the first stage of the 24th Olympiad.

[Kostero]

Similarly https://szkopul.edu.pl/task_archive/oi/24/ should lead to a view with all the problems from the 24th Olympiad.

[DietPawel]

I like the feature, but I would like to discuss the way it is implemented. Currently there are many slugs for different competitions, for example OIJ uses legacy name OIG. I am not convinced that all task archive problems should have uniformly made slugs. I think we should either:

• Enable customization of such link structures
• Make quick links for problems which can be generated automatically for task archive, but editable.
• Make an external service for general url shorting, with integration with task archive.

Additionally this should add some UI features for displaying quick links for users to find out about their existence