Switch to VSCode/Calva as the main IDE in the examples

[tengstrand]

Is your feature request related to a problem? Please describe.
The documentation uses Cursive today in the examples, which isn't free. An open source solution could help people getting started with Polylith more easily.

Describe the solution you'd like
Calva is a good choice. The latest GitPod based solution that allows you to run the IDE in the browser is also a plus.

Additional context
Add a section for the other main IDE's, Emacs/CIDER and IDEA/Cursive.

[seancorfield]

And a reminder that the upcoming (as of Jul/5/23) version of Cursive will have proper support for Polylith workspaces so the :extra-paths workaround could go away too :)