RFC: Sane rectangle class

[Jan-Marek Glogowski]

FWIW there is also canvas/source/tools/surfacerect.hxx, which might be
the lowest hanging fruit to get rid of, and which I found when fixing
tdf#40534 :-)

If you replace this as a starter, we would at least not have the "just
and additional standard" situation and keep our Rectangle type count
equal ;-)

And there is also basegfx::B2IBox. Naming is hard.

Probably it would also make sense to fix SalGraphics::drawRect.

I would be happy, if I don't read comments like

// a size of [0,0] therefore denotes a one-by-one rectangle.

in the future.

Jan-Marek