Add lax-css, lax-markup, and lax-sql plugins

[bartlomieju]

Adds three Wasm formatter plugins from the lax family to the registry:

• bartlomieju/lax-css (configKey css) — CSS, SCSS, and Less.
• bartlomieju/lax-markup (configKey markup) — HTML, XML, SVG, Vue,
  Svelte, and Astro.
• bartlomieju/lax-sql (configKey sql) — dialect-agnostic SQL.

Each is published as a single plugin.wasm asset on its own GitHub repo and
already resolves through the redirect service, e.g.
https://plugins.dprint.dev/bartlomieju/lax-css/latest.json. They build against
dprint-core 0.67.4.

All three are marked "selected": false. lax-css and lax-markup are
alternative implementations overlapping the existing malva and markup_fmt
plugins, so they are intentionally left out of the default dprint init
selection to avoid clashing with those.