Smarter mouse motion event compression in Qt

QTBUG-44964 added AA_CompressHighFrequencyEvents, but it is not a very good solution as applications frequently do not want to process events at full frequency, but would like to receive information about the full motion of the mouse pointer. The solution is to compress the delivery of mose motion events, but include information about the compressed motion events by adding API like this:

class QMouseEvent : public QInputEvent {
public:
    ...
    QList<QPoint> compressedPositions();
    QList<QPoint> compressedGlobalPositions();
    ...
};

I suggested the same in a comment on QTBUG-44964 but since it could not easily be added without breaking the ABI, it never got any further. I am adding this issue now to have it considered for Qt 6.