Include example HTML5 Drag and Drop API

There is a chapter called [“Drag'n'Drop with mouse events”](https://javascript.info/mouse-drag-and-drop), and it makes a passing reference to the Drag and Drop API. There are plenty of cases where it’s appropriate to choose this approach.

However, I think there also needs to be a “Drag'n'Drop with the API” chapter.

I’ve been using the DND API on a learning project. Although I got over the strange hurdle of learning which events apply to draggable items and which events apply to drop zones, I’m at a point where I am really missing the awesome guidance I can find on most other topics in your excellent work.

For the purpose of inspiration in creating such a chapter (or for anyone else reading this), one tutorial I found helpful helpful is this video (which includes the basics of the DND API, and implements a list-sorting feature):

https://www.youtube.com/watch?v=jfYWwQrtzzY

Leggi il capitolo esistente «Drag'n'Drop with mouse events» all’indirizzo https://javascript.info/mouse-drag-and-drop e rivedi il video tutorial citato per verificare la copertura della HTML5 Drag and Drop API. Il lavoro sarà considerato completato quando sarà stato aggiunto un nuovo capitolo che spieghi l’API, inclusi gli eventi di draggable-item e drop-zone, e fornisca indicazioni pratiche su quando utilizzarla.

Scritto dal modello di indicizzazione a partire dal testo della issue.