WIP: Switch from hydra to google oauth

Apart from a useful tidy up that allows running the frontend (and npm) in a container, this MR is a unsuccessful attempt at switching from hydra to google-oauth2.

With correct env.local and config.local.js (with Client ID that allows localhost:3000 and callback oauth2-callback.html) then the authentication to google works but I've been unable to get the next call to the exchange token api endpoint to work.

This has been a nightmare of redux rabbit holes!

Attempt at #176 (closed)