Remove standalone dev server
Currently we use a standalone express dev server to run the client-side webpack compiler:

https://github.com/ream/ream/blob/d96bae0f853a37b1d2955994f9ce1c73da92b24a/packages/ream-core/lib/setup-dev-server.js#L7

And we use a proxy in the actual http request handler to serve webpack assets from the dev server:

https://github.com/ream/ream/blob/d96bae0f853a37b1d2955994f9ce1c73da92b24a/packages/ream-core/lib/index.js#L142-L150

maybe we can simply attach those two middlewares (webpack-dev-middle-ware & webpack-hot-middleware) to our request handler instead of creating a new dev server.