Streamlit-login POC

Uses the newly released st.switch_page and the yet-to-be-relased st.page_link to show how you can create an app that:

1. Only shows the login page if you're not logged in
2. Redirects to the login page if you try to visit another url
3. Shows custom page links with emojis in the sidebar once you're logged in

Check it out at https://app-app.streamlit.app/