feat: integrate vite

links: https://gitlab.developers.cam.ac.uk/uis/devops/tech-lead-forum/-/issues/19

Changes:

1. Removes CRA dependencies and adds dependencies for Vite.
2. Uses yarn instead of npm.
3. Removes old testing directories so test can be run multiple times.
4. Moves index.html to root on ui_module.
5. Applies changes regarding frontend building directory.