Drop QGraphicsView classes in PaintData

QGraphicsRotation and Scale are QObject wrappers. It's not useful in
data structures where we're creating mulitple of these every frame. It's
large enough to appear in hotspot as taking over 1% of a regular frame.

We don't even use the QGraphicsRotation mapping inside scene for a
reason, so it's not giving us much.

It's technically an API break in libkwineffects. Pragamatically no-one
would use these. We also lose QGraphicsScale's origin, but we never
exposed this in PaintData's public header.