example: Interactive WidgetLayer

[pamtbaau]

This PR adds a new example showing the newly added interactivity option on WidgetLayer. This PR builds upon PR #213 which add interactivity to widgets in the WidgetLayer.

Example allows user to:

• Long tap map: Add marker.
• Tap marker: Show dialog.
• Long tap marker: Show popup menu.
• Tap+drag marker: Move marker around. When drag ends, user is asked to accept/discard the move.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 40.77%. Comparing base (9a43395) to head (6afc499).
Report is 1 commits behind head on main.

[josxha]

Thanks @pamtbaau!
I added some small changes to this pr and #213 to bridge the gap between android and web and make it work on web, too. 👍

[pamtbaau]

Thanks for reviewing, fixing, improving and merging my PR :-)