message: Create API Overview doc
diff: + [Roadmap](./docs/roadmap.md)
  + [Contributing](./contributing.md)
  + [Code of Conduct](./CODE_OF_CONDUCT.md)
  -* API
  +* [API](./docs/API.md)
  + [render](./src/render.md)
  + [Page](./src/components/page/Page.md)
  + [Frame](./src/components/frame/Frame.md)
  