Svelte: Reorderable List example

[rlaferla]

I'd like to contribute this example. It does not work on mobile which would require DOM Touch support but I think it's still very useful.

https://svelte.dev/repl/e5d53d675f444311a908121494f51aa6?version=3.15.0

[rlaferla]

I have an improved example that now works on both desktop and mobile:

https://svelte.dev/repl/2cf25d5fd92b4163a356679c4315d386?version=3.15.0

[zahachtah]

I really like this but I was trying some things and the performance deteriorated quickly.

just as a test I had 3 span elements in the item container and after dragging a few times the animations seem to start lagging and doms get stuck in weird places...

https://svelte.dev/repl/f2bac9839a0e4646ba9d9caab38af47d?version=3.15.0