1. The update to Streamlit 1.13 has bee mirrored
2. Streamlit needs to be in Headless mode so it doesn't pester about
wanting an email on startup, which crashes in docker since there's no
stdin
3. Fixed an issue where opencv-python from the base image was not
allowing us to override it with opencv-python-headless, which is
required because of its lack of runtime DLLs (+ it's smaller)