Get Cypress up and running again (with docker and interactive testing)

[Splines]

This PR does not rework the cypress tests. Instead, it sets all the necessary infrastructure to run cypress tests locally and in our GitHub Actions pipeline without a big fuss.

Start cypress interactive GUI

This may be subject to frequent changes as this PR is only a draft right now.

• Install VcXsrv Windows X Server. Run XLaunch. In the "Extra settings", make sure to choose "Disable access control".
  This is not needed anymore, new versions of WSL come with an X11 server, yeah 🙌 See the WSLg repo.
  The only thing you have to do is run wsl --update (in Powershell).
• To start Cypress with the interactive test runner, execute the following command inside the docker/test/ folder:

docker compose -f docker-compose.yml -f cypress.yml -f cypress-interactive.yml up --exit-code-from cypress

Wait a few seconds and the GUI should automatically pop up. Choose E2E testing and try to run the submission dummy test I've added. You should see the edit profile page at the end.

Note that cypress shares the test database with the Rails unit tests. This shouldn't be a problem as they both clean the whole database before they execute anything. But this means, we shouldn't run cypress and unit tests at the same time. I don't feel like this is a big issue locally, if you feel it is, it's easy to spin up another docker environment.

cypress-on-rails & more links

We don't use cypress-on-rails anymore.

• on-rails.js
• Example for Authenticating a User (did not work)
• A more succinct authenticating example -> that one works ;)
• Official cypress guides for authenticating efficiently
• A long list of Cypress Recipes

TODOs

• Add Cypress back to CI/CD
• Use GitHub Actions formatter -> I've opened a feature request here -> ▶ probably not available right now, so will do in future PR
• Long-term: write more robust cypress tests following best practices. The starting guide is also a good resource. -> ▶ will do in future PRs
• Fix ESLint errors in cypress files (these are not visible here in the pipeline as we didn't change these files)
• Implement clean login mechanism in combination with app scenarios, unify interfaces
• Provide just commands for easy startup of cypress GUI -> ▶ in future PR
• Maybe find a better way than X11 server, see here and my StackOverflow question.
• Add Cypress section to wiki

[fosterfarrell9]

LGTM. Great work!