Delete Level: Categorize warnings

[dplumb_BWBR]

I love that now (2019? 2020?) when you delete a Level, it tells you what elements you're going to lose.

However, much of what gets deleted is expected and not significant.

The significant parts are hard to find.

When I delete a Level, I would expect that any Views belonging to that Level would be deleted, along with any annotation on those Views.

I wish the Warning dialog would be grouped by Annotation, Views, and Modeled Elements.

I probably don't care that 187 Dimensions will be deleted, but I do care about the Model Elements that those Dimensions are attached to.

If I could expand or collapse Annotations and Views, it would be much easier to focus on the elements that are getting deleted.

[steiner]

Hi, there should be as well the possibility in a grafical manner to get an overview which elements will be deleted. For example theese could be isolated in a 3D view. For the moment they is a third parti plugin ( https://twentytwo.space/2020/02/09/element-selector-pro/ )who allows this with some additional steps. 

The possibility to relocate elements that one would like to keep on another level would be the logical consequence.