Use Original Element for Ghost

[zerosym]

Currently the ghost is cloned from the dragged item, and the original is left in place with visibility:hidden applied. The ghost is then appended to the container.

There are a few issues with this that I've come across:

• Jank when ghost is cloned from an element with a lot of child nodes. Honestly, not sure how much not cloning and using original would improve this.
• Cloned ghost does not respect the scroll position of nested content. In these situations the drag becomes a bit jarring to look at.
• Having the ghost inserted into the container as the last element makes for more annoying CSS selectors, since you can no longer use :last-child.

A look at how Trello handles it... they leave behind a simple div placeholder and move the original item out of the container into an upper level body div.

[zerosym]

Just a quick demo of the scroll issue.

https://codesandbox.io/s/pkx885prpx