Remove force geometry flags

With the client-side decoration changes, kwin will properly determine whether the window needs to be configured even if the frame geometry has not changed.

This change slightly changes the semantics of the setFrameGeometry() method. Prior to this, it was possible to force a geometry, i.e. block other geometry updates, however such a behavior is counter-intuitive and it exponentially increases the complexity of code.

As far as I know, the force flag was needed to propagate geometry changes if the frame geometry doesn't change, but the client geometry does. With the client-side decoration changes, the force flag is not needed, as kwin now takes into account the client geometry and the frame geometry when determining whether to send a configure event.