Replace Stickler CI with GitHub Action for eslint

[flowirtz]

Currently we are using Stickler CI to run eslint on every PR.
Via #26 we discovered an issue with this setup however:

All imports for my new PostNavigation.jsx file are failing linting. So I looked into the import/no-resolved lint error a bit. This has to do with the .eslintrc.js file. May need to change some settings.

When Stickler CI runs ESLint it does not install any of your repository dependencies. Because of this, rules that operate on import checking or typechecking rules will likely not work.

From https://stickler-ci.com/docs#javascript

Originally posted by @sukhbeersingh in #26 (comment)

For now we disabled import checking rules via #29, this can't be permanent however, it might introduce bigger issues into the codebase.

There is this GitHub Action which does the same thing but is now archived: eslint/github-action. It says:

The GitHub-created actions/setup-node already supports annotating ESLint errors on commits and pull requests. Please use that instead.

We should setup some GitHub Action that installs the dependencies and then runs the lint script.