[Research] Use an existing library for the viewer's drag/rotate/resize

[Zulko]

Motivation:

Right now the handles to rotate and resize are home-made and don't look incredible. Existing frameworks could make them better.

Specs:

• As before, the resize/rotate handles only appear when hovering an element
• Drag/Drop/Resize now works with the new framework.
• The asset crop preview (which also uses a drag-and-resize widget) works well with the new framework.

Technical details

• JS frameworks: moveable has a vue binding
• Vue frameworks in particular: vue-drag-rotate-resize
• There may be more!