VitePress on Vapor

Repo: https://github.com/sxzz/vitepress-vapor

- [x] self reference
- [x] class inherit
- [x] scope id inherit
- [x] `<component>`
- [x] [`createBranch`](https://github.com/vuejs/vue-vapor/commit/59975ed36b8945c954f52f97d93d1c5f704a3137) API
- [x] valid slot
- [x] destructure in `v-for`
- [ ] `@vue:beforeMount` hook
- [ ] `Transition` component
- [ ] async component
- [ ] SSR