expose connect app from http transport

[shanejonas]

I need to app.set('trust proxy') as seen here since heroku is behind a proxy.

server-js/src/transports/http.ts

Line 20 in fc7ace8

const app = connect();

[piboistudios]

This would also be nice in general, as I'd like to use OpenRPC alongside OpenAPI. Since connect/express apps are just handler functions, having access to this would let users plug OpenRPC into their existing projects.