build(lint): use native stylelint config resolution

[uncenter]

Prevent errors on custom elements in #346, see #346 (comment).

[nekowinston]

I really liked the added typo protection that selector-type-no-unknown added, and I think it's rare enough where a workaround for each userstyle isn't that much effort. I'll push what I came up with.

[nekowinston]

Lichess lint passes for me when I create ./styles/lichess/.stylelintrc.json with:

{
  "rules": {
    "selector-type-no-unknown": [
      true,
      { "ignore": ["signal", "index", "fill"] }
    ]
  }
}

[nekowinston]

8ed27aa works but this really isn't getting any more maintainable.
Luckily it turned out that turning on nodeModulesDir and not passing in config into stylelint.lint does everything we want for us.

The config file will have to include an extends to the repo root, compared to the previous impl:

{
  "extends": "../../.stylelintrc.js",
  "rules": {
    "selector-type-no-unknown": [true, { "ignore": ["signal", "index", "fill"] }]
  }
}

[nekowinston]

Think this should do it.

[uncenter]

That's way better, thanks!