[Layout] Support positioning and stacking order

[kyledurand]

To achieve coverage within our own codebase We need access to things like:
position: relative | absolute | fixed | sticky etc..
top: Spacing; left: Spacing; right: Spacing; bottom: Spacing
z-index: StackingOrder
clip
visibility
opacity

These last few could have been handled by the VisuallyHidden component but that's now deprecated. Should we un-deprecate for non string hiding?

These properties seem like they should be added to a new component but also easily added to Box.

Box by our own definition should only expose access to our tokens but it's already doing more than that with things like width, (min/max)-width, overflow, min-height etc... We could move these to the new component if need be