Remove QMetaObjectExtraData and put everything into QMetaObject

Remove QMetaObjectExtraData and put everything into QMetaObject

QMetaObjectExtraData was added when support for QMetaObject::newInstance
was added. One needed a place to put the pointer to static_metacall in
the QMetaObject.

But as we break binary compatibility, one can change the size of
QMetaObject, and put everything back inside QMetaObject's own structure.
Meaning it is not required anymore to have one QMetaObjectExtraData
instance per QMetaObject anymore.

Change-Id: If0b8f586cbaf633eed10045adee3ba3366826c86
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
Reviewed-by: Kent Hansen <kent.hansen@nokia.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@nokia.com>