[API] Swagger/OpenAPI Docs

Awesome idea! I just wanted to mention that there’s also https://github.com/scalar/scalar as an alternative to Swagger UI. Happy to help here :)

@xC0dex Yep that's why I said OpenAPI docs so anyone can use whatever frontend they'd like :3 I have no idea how it would be implemented with Fluxer, since I don't really know anything about the Hono framework, but I assume that it would be possible. Also having OpenAPI docs would make it significantly easier for contributors and/or Hampus to work on the documentation.