Add multiple language support

[Supergecki]

Is your feature request related to a problem? Please describe.
Currently, there is only an English version of the wiki which makes it hard for non- or not-so-well-English speakers (especially younger students) to understand the docs.

Describe the solution you'd like
Add multiple language support so the documentation is also available in other languages (especially German).

Describe alternatives you've considered
Hosting multiple wikis or having no non-English wiki at all are both really impractical.