Lecture Week view

[MariusAlbrecht]

Describe the solution you'd like
Ordering option in weeks. Numbering relative to the lectures, so that the first lecture is in the first week and the last lecture in the last one.

Describe alternatives you've considered
Figuring out how many lectures per week take place and then count. Is absolutely feasible but not convenient.

Additional context
Lectures are often structured in weeks internally, e.g. there would be Tutorial(sheets) 1-12. This feature would reflect that structure and make it easy to find the corresponding lectures, e.g. the ones sheet 6 is about.