Support Svelte

I'd like to add support for svelte. There even is a branch with the package to do the job: [`svelte`](https://github.com/theemo-tokens/theemo/tree/svelte) However, the `@theemo/vite` plugin cannot be used with svelte as-is. Svelte apparently does not support the full vite plugin API. Some shenanigans is needed, see: https://github.com/sveltejs/kit/discussions/8269