Add Selenium tests with js code coverage calculation

[KowalskiPiotr98]

- [ ] Figure out how to calculate js code coverage along the way and restore .js files coverage calculation in Sonar.

[KowalskiPiotr98]

Moving this to the current project as Sonar is getting more and more annoyed by having no js code coverage.

[KowalskiPiotr98]

Okay, calculating code coverage of JS based on selenium might be a bit dumb, so I will exclude all js files from coverage, but instead make sure to thoroughly test this thing with selenium.

[KowalskiPiotr98]

The tests have been all pretty much written already, so all that's left to do is to figure out how to run this properly (will most likely need a one docker-compose.yml to rule them all).

Have something like an "experimental" docker tag that's just built on every push to main and use that in this docker-compose file (put this file in the main repo).