Use actual web browser for oauth login
goa and e-d-s replaced integrated webkitgtk auth flow by opening the authentication URL with a regular web browser and getting response by specifying a custom protocol as the redirect URL. This has several benefits:
- Allows using the web browser’s password manager.
- Better trust that the URL is actually proper site rather than a phishing.
- One less dependency needed to bump during the eventual GTK 4 port.