Add Gradio authentication support via command line arguments

[kldzj]

Summary

This pull request introduces an authentication layer to the Gradio web interface. Users can now secure the application by setting a username and password, which can be provided either through command-line arguments or environment variables.

Changes

• CLI Arguments Added: Introduced --username and --password arguments in app.py to receive authentication credentials.
• Environment Variable Support: The application now reads credentials from GRADIO_USERNAME and GRADIO_PASSWORD environment variables.

Additional Notes

• Usage: To enable authentication, run the app with both arguments (e.g., python app.py --username admin --password your_password). Alternatively one can set the specified environment variables to do so.