Debug: contribute a start view

Hi 👋 VS Code dev here,

Last milestone we have introduced a Start View for debugging. More about this can be found here https://github.com/microsoft/vscode/issues/84677

Using the context key debugUx which can have values simple or default any extension can contribute a view to the debug start experience.
Thus I am proposing that python considers contributing a view that can improve the start experience for new users not familar with python debugging. I am not a python expert but I suspect that there are quite some python specific actions which could be useful for new users.

If you think this is a good idea we can also work on fine tuning this start experience. We would also need to check for context keys of active editor to only show the view when the user has a python file opened.

For reference here's a picture how the debug start view looks now for python

fyi @qubitron @DonJayamanne