Use new code formatting approach since ESLint deprecated all formatting rules

[chrismayer]

Since V8.53, ESLint team decided to deprecate all formatting rules. More info can be found on this official announcement.
To keep it simple, those rules will stay at least in version 9 of ESLint but will not receive any updates anymore. Those rules should be abandoned in favor of a code formatter OR replaced by the rules defined in [@stylistic/eslint-plugin-js](https://eslint.style/packages/js). This package contains all the deprecated rules and will be maintained. However, as our main dependencies (eslint-plugin-vue and eslint-config-standard) don't make use of those rules yet, it is better to wait before making the transition on our side...

This issue is derived from #377 and the text above was initially provided by @sronveaux .