Explore how to improve the display of progress bars (given use of stlite)

[Bergam0t]

Progress bars and the spinner work slightly differently in stlite but they are working much better in the streamlit_hello app below than I have managed to get them working in this app at present.

https://edit.share.stlite.net/?sampleAppId=streamlit_hello

Take a look at that code and see if it helps improve the implementation here.