Stop using QAXFACTORY_DEFAULT macro

The ActiveQt QAXFACTORY_EXPORT and QAXFACTORY_DEFAULT macros are redundant, and client code can be easily rewritten to instead use the QAXFACTORY_BEGIN/QAXCLASS/QAXFACTORY_END macros. I'm therefore proposing to deprecate these macros, so that they can later be removed in Qt 6. The only "ripple" effect that would cause, is that "ClassID", "InterfaceID", "EventsID" then need to be converted into Q_CLASSINFO metadata.