add own class name hashing

[jantimon]

This PR is a first draft for minified CSS class names in production by generating deterministic but unique class names directly in the SWC plugin

The change will:

• reduce the class name size in css file (upto 20% gzip file size savings)
• reduce the ssr html size (because the class names are also used there)
• reduce the js bundle size (because we can skip the mappings and the class names are also there)

The generated code from the SWC plugin changes from

import styleYak from "./input.yak.module.css"; 
styled.button(styleYak.Button);

to the following:

```tsx
import "./input.yak.module.css";
styled.button("Button_m7uBBu");

The PR will only work for Next.js versions with a postcss-modules-local-by-default version 4.1 or newer

Still todo:

• Test if single line comments // work for postcss ignore markers
• Update css-loader imports from cross-file selectors and mixins to use the new class naming scheme

[changeset-bot]

🦋 Changeset detected

Latest commit: 7ffa69b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
yak-swc	Minor
next-yak	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[codspeed-hq]

CodSpeed Performance Report

Merging #220 will not alter performance

_{Comparing custom-class-naming (7ffa69b) with main (07bed79)}

Summary

✅ 2 untouched benchmarks

[jantimon]

This PR reduces CSS by over 20% it also reduces the js size

Overall it saves 10% after gzip for the example app (excluding next.js framework files)