Update sortable documentation with better examples for Handle and Remove

[zampa00]

When checking the examples documentation, it's shown that it's possible to create an item with a draggable handle or a button to remove the item.

When clicking on "Show code" for Drag Handle, it only shows () => <Sortable {...props} handle />, but it looks like Sortable is not an importable component, but just a component created to test the implementation and produce a playable documentation.

If there is an easy way to implement a drag handle, it should be pointed out somewhere in the documentation.

[mirorauhala]

There's some example code given on the draggable documentation page. Read more at https://docs.dndkit.com/api-documentation/draggable#flexibility