Consider changing internal representation of Rect for more float safety

[ffreyer]

Using origins and widths means that all the vertices except for origin have (potential for) float precision issues. For example, if we wanted a (Float32) Rect from -1f10 to 500 we would instead get:

julia> Point2f(-1f10) + (Point2f(500) - Point2f(-1f10))
2-element Point{2, Float32} with indices SOneTo(2):
 0.0
 0.0

julia> coordinates(Rect2f([Point2f(-1f10), Point2f(500)]))
4-element Vector{Point{2, Float32}}:
 [-1.0f10, -1.0f10]
 [0.0, -1.0f10]
 [0.0, 0.0]
 [-1.0f10, 0.0]

because eps(-1f10) = 1024f0 can not resolve 500.

For reference, I hit this here: MakieOrg/Makie.jl#4911