Migrate to vitest
This MR migrates the tests to vitest.
I think this migration is benifitial for us because of the following reasons:
- vitest is faster than jest
- vitest has typescript support out of the box (should resolve issues with weird code coverage)
- the GEMIMEG-Tool will use vite aswell at some point in the future (because of Vue 3 and Nuxt)
Edited by Jan Loewe