Variants API Support

[artmsilva]

Is your feature request related to a problem? Please describe.

We are considering StyleX for our design system. We are moving away from Stitches.js. However there are a lot of features of Stitches.js we like such as their "variants" API and "$<token" syntax.

Describe a solution you'd like
It's not really a problem or a feature request. Curious if the maintainers know if it's possible with StyleX to build something similar either internally or externally atop of StyleX's API.

Describe alternatives you've considered

Additional context

[necolas]

The pattern for variants is documented here https://stylexjs.com/docs/learn/styling-ui/using-styles/#style-variants