Improve structure of flipcards and mc questions

[LuisHeinzlmeier]

• Currently, our flipcards and MC-questions are simply placed one below the other. With many questions, this can appear overcrowded. Is there a way to structure them more nicely into dropdowns, tabs, grid/table, or a slider, for example?

• The cards for flipcards and MC-questions do not have the same size. At least when they are displayed next to each other in the future, this will be noticeable. Is it possible to make the two card types the same size?
• Maybe add jupyter-book/src/lib.py to a new folder in scripts and remove jupyter-book/src. Then we collect all Python scripts in one folder.