Reuse listfield gadget for the rendering.

Dynamically add/remove listfield to improve usage.

Try to reduce number of DOM modifications.
Display value even if not present in the item list.

Use an html5 input subgadget to handle the DOM events

This reverts commit fa128ff7.

This is only cosmetics.

Hard links are only used for the initial clone.
On next runs, the working copies diverge and this wastes space on disk.