Add option to NOT nest the element

[desto-git]

Finally with scrollbar-width there's also a way to hide the scrollbar in Firefox without breaking it's scrolling functionality.

Now all major browsers support a way of hiding the native scrollbar. As such, it's legitimate to offer an option to not wrap the element into an overflow: hidden; container.

Benefits:

• it does not mess with the elements
  • no care needs to be taken when working with the target element in JS
  • referencing elements inside it before using scrollbarjs.add() no longer breaks the reference
  • adding scrollbars to be body has no side effects (especially autohiding url bar on mobile)
• styling
  • scrollbars can overflow the content, thus can be placed outside the viewport
  • no need to handle direction: rtl;
  • no ::after workaround to add padding to the bottom needed

[HighCoordination]

Would be nice to see it in action 🥳.

This would be also a very good "selling point", because there are many alternatives with the current (nesting container) approach, but none of them supports both: native scrolling without content wrapping see https://kingsora.github.io/OverlayScrollbars/#!faq