When the redirect_uri has a special value for OOB authentication, display a page prompting the user to copy and paste the code back to the application. Use the code as the page's title as well.

This is useful when it's not practical for the client to run an HTTP server and use a localhost redirect uri, such as when it's executing on a remote machine.

References:
- https://github.com/googleapis/google-api-python-client/blob/main/docs/oauth-installed.md#urnietfwgoauth20oob
- https://developers.google.com/identity/protocols/oauth2/native-app#step-2:-send-a-request-to-googles-oauth-2.0-server