Add support for authorizers in websocket APIs

Using @app.router I can define an authorizer field argument to configure authorization layer. In API gateway, I can create a lambda authorizer for $connect, but in @app.on_ws_connect I don't have the authorizer field.

How can I achieve that?

Start by reading the @app.on_ws_connect handler and the @app.router authorizer argument, then compare them with API Gateway WebSocket authorizers for $connect. Define what authorizer information should be available during connection handling and verify the behavior with the relevant WebSocket integration tests.

Written by the indexing model from the issue text.