Users should use range constructors instead to do the conversion.
Keep conversion methods between QList and QVector as these will turn
into a no-op in Qt 6, whereas forcing people to use range constructors
would lead to deep copies of the data.
Change-Id: Id9fc9e4d007044e019826da523e8418857c91283
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>