chore: Extract CSS instead of injecting

[susnux]

📝 Summary

This will create a CSS file per entry point instead of injecting the CSS. Dynamic chunks will still import their CSS by them self.

Alternative for #6025

🏁 Checklist

• Code is properly formatted (npm run lint / npm run stylelint / composer run cs:check)
• Sign-off message is added to all commits
• Tests (unit, integration and/or end-to-end) passing and the changes are covered with tests
• Documentation (README or documentation) has been updated or is not required

[juliushaertl]

Is there any benefit or downside comparing the two options form here and #6025?

[susnux]

Extracting:

• Smaller JS assets as the CSS is not included, this will significantly reduce the browsers JS parsing time
• Let the browser handle styles and not rely on the injection logic (this means we utilize addStyle so we support nonces on them e.g. if we in the future forbid unsafe styles (CSP)

Injecting:

• No need to care where the scripts are used the styles are always injected automatically

[juliushaertl]

Thanks, then I'd say extracting is the most sane.