fix: remove yarn.lock and restore rc files

[SilasPeters]

We currently use two packagers: npm and yarn. This is bad, and I thus propose to switch to npm.

Furthermore, in the vite PR we removed some .*rc files, which does not seem nessescary as far as I understand, and it would be better to keep them.

All linters seem to work, but see the other comments on why I am unsure to merge this.

[SilasPeters]

I was told that we don't use babel anymore, but lot's of babel dependencies were still found. I don't understand react enough to judge if everything is alright now.

[SilasPeters]

After talking to @josvanos , we solved everything!

The babel linter and the linter jshint linter are no more, eslint now does everything.
Some old or weird linter rules have been removed.

Lastly, we cleaned up lots of things, and added an editorconfig file.

In another PR I will remove all warnings of the linter, and in a follow-up PR I will create a pipeline that tests if the linter passes.

[stickyPiston]

[...] and in a follow-up PR I will create a pipeline that tests if the linter passes.

The CI pipeline proposal in #112 already includes a lint check before building: we simply need to merge this PR's branch into it to get that to work.

[josvanos]

As seen in the build.yml pull request, changing the lint command from 'eslint .' to 'eslint src' would be better. You can remove the ignore dist folder line in the eslintrc this way!

[stickyPiston]

頑張った！