Introduce scss linting to codebase

[blyedev]

Description

Disclaimer: this PR is purely the result of the fact i was experimenting with tooling and needed a larger codebase to do so.

In here I add stylelint which allows you to spot issues in your scss such as duplicate selectors, prefixes that shouldn't be there because of tools like autoprefixer and many others. Each issue comes with a rule name which has some solid reasoning behind it on their website.

Judging by the current output it needs fine tuning to adjust to the code-base conventions such as selector-case since there's a lot of classes with camel case. But given scss conventions maintainers might elect to conform to the recommended rules.

Perhaps the coolest part of this PR though: The formatter on the lint:scss:ci script makes GitHub highlight all errors directly in the code so you get something akin to an automatic code review. So if you enable GitHub actions on my PR you will see every error raised without having to run it locally

From the 1800 issues about 800 are auto-fixable, I did not do that in this PR because I do not know this code-base nearly well enough to do so confidently but if I receive approval I will gladly fix all the issues mentioned by the linter

Issues Resolved

List any existing issues this PR resolves

Check List

• New functionality includes testing.
• New functionality has been documented in the README if applicable.

[github-actions]

Hello there blyedev! 👋

Thank you and congrats 🎉 for opening your first PR on this project! ✨ 💖

We will try to review it soon!

[johannesjo]

Hey there! Thank you very much for opening up this PR. While I support adding stylelint I am currently developing a bigger new feature, which I like to merge back to master before doing such a wide ranging change. Would it be alright if I ping you once that is done?

[blyedev]

Sure