Mini timetables should also work with parallel lessons

Also, please beautify the design.

Also, provide a loading animation.

For reference, it was possible in the past in a nice way:

changed milestone to /AlekSIS%"[NLnet #1 (closed)] Fix existing bugs with new timetable"

added part::frontend type::bug labels

assigned to @ZugBahnHof

changed the description

created branch 45-mini-timetables-should-also-work-with-parallel-lessons to address this issue

mentioned in merge request !39 (merged)

mentioned in commit 363daa54

closed with merge request !39 (merged)