Read environment variables from .env file

[surchs]

In development, it's pretty involved to always export a local .env file to the local shell in order to test setting changes. It can also lead to strange behaviour when I forget that I had already set a variable in my shell, but then change the .env file without re-exporting it.

We should find a way for the local .env file to be automatically read by the development server so that I can

• make a change to a ENV variable in the .env file
• not export the .env file
• see the change in the .env file applied to the behaviour of the app after a relaunch (ideally automatic relaunch from vite dev-mode)