Feature: Sortable Tree

[0-don]

Good job on the DND lib.

The only thing missing to make it perfect is a sortable tree, like this example: https://master--5fc05e08a4a65d0021ae0bf2.chromatic.com/?path=/story/examples-tree-sortable--all-features

[gabrielmfern]

@0-don You can get it working with the current APIs with a bit of effort