Qt copyrights are now in The Qt Company, so we could update the source
code headers accordingly. In the same go we should also fix the links to
point to qt.io.

Change-Id: I2febb46d711c51eeb08f13418a4fc15ab0502f1a
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>