Research Popover API usage (for non-modal?) dialogs.

Definitely great for the off-canvas "rewrite" in 🐛 Module breaks Layout Builder or any module using the core "drupal.dialog.off_canvas" library Active !

Hey gang, I finally came around to finding this issue. I've done some preliminary work here. It might be good to discuss the approach we want to take. Drupal provides a whole separate render path for dialogs, along with a custom Renderer and drupal ajax support.

What are the goals here? Is it:

* Feature parity with Drupal core?
* A means to inject a different implementation of the dialog that completely replaces the off-canvas dialog with a new implementation?

Let's discuss