improve dx for codespaces

[b8daniel]

I've tried opening and starting the project in a codespace e. g. for code review.
I couldn't fully get it to work, but almost - here are some things I found.
It's all mostly related to how gh forwards ports as urls without a port

• set WDS_SOCKET_PORT=0 for react-scripts start because the dev-live-update-server port isn't 3000 after the gh port forwarding
• the URLs in .env.development need to be changed to the appropriate forwarded urls
  • these are generated in the format https://CODESPACENAME-PORT.app.github.dev, CODESPACE_NAME is an enviroment variable

I'm currently hitting a wall with the backend server:
For cookies and redirects, the backend is using the r.Host() which is localhost:3000 but when the client needs to request something, the request must go to https://CODESPACENAME-8080.app.github.dev.

could we maybe add an option either as cli parameter or enviroment variable to overwrite the host on the backend?

also let me know if there is anyting else you'd like to have in the codespace besides go and node runtimes.