Create a custom `WebSocketRoute`

[Kludex]

Unfortunately, the APIWebSocketRoute decorator from FastAPI doesn't give us much information. We need information to enrich our asyncapi.json.

Hence, the proposal here is to create a custom WebSocketRoute class that allows some extra fields that can be used by AsyncAPI.

[DjaPy]

I can help.

Show me what's not missing in class WebSockerRoute

[Kludex]

We need to populate the asyncapi.json... I'm not sure which fields we want, but we'll use them to populate it.

[Kludex]

FastAPI doesn't support custom WebSocketRoute classes... We need to create a custom APIRouter as well.