Add ability to cascade elements programmatically

[MaherKSantina]

It would be nice to have operators to cascade elements vertically and horizontally.
For example, if I have 2 views View1 and View2, and I want to place them below each other in a reusable view, I can do something like this:

let view = VerticalCascading(View1() + View2())

or

let view = VerticalCascading(View1() + .spacer(size: 20) + View2())