Refine qt-module dependencies for massively parallel builds

QtWebKit should be build after QtMultimedia for multimedia support on Mac
and Windows.

QtScript should be build after QtTools because an example uses UiTools.

Change-Id: Id92efac72d8c2c2237f21fad1ab823c1c1ac95dd
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>