website: Fix SortableItem whitespace and improve cursor handling

[rjmacarthy]

Hey, this pr fixes issue #1364 and also applies some refactoring of the code in SortableItem.

Here is a a summary of the changes:

• Replace useState hook to manage the mouse cursor. Instead, we can use css.
• Added a background color indicator when the item is in active state.
• Added and updated the stories for Sortable to support these changes.

Any problems please let me know.

[github-actions[bot]]

:x: pre-commit failed. Please run pre-commit run --all-files locally and commit the changes. Find more information in the repository's CONTRIBUTING.md