feat!: bring back stylistic rules

[susnux]

For ESLint we are doing the same due to missing consensus on moving to prettier and the already large user base of @nextcloud/eslint-config and @nextcloud/stylelint-config.

[ShGKme]

and the already large user base of @nextcloud/eslint-config

Speaking of that, ESLint is also capable of linting and formatting CSS

https://eslint.org/blog/2025/02/eslint-css-support/

[ShGKme]

Do we want to use stylelint to fix formating in <style> block in .vue files (which is kind of a JS module)?

[susnux]

Speaking of that, ESLint is also capable of linting and formatting CSS

IIRC and from reading it, the rules are still quite minimal.

Do we want to use stylelint to fix formating in <style> block in .vue files (which is kind of a JS module)?

We already did this in the past and doing it also currently, so I would not change it.

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Basically this reverts only the Prettier decision as basically no app (except forms) that I know migrated and the standards RFC was never decided and it seems to be easier to revert back to also include stylistic for now.
As otherwise apps currently updated the config and now start to get more and more weird formatting in the styles due to missing rules (e.g. spaces vs tabs, missing spaces around arithmetic operations etc - all that stuff we enforced in the past already and should be enforced by prettier).