Round 1 - focus on headers.
For classes with initial in range [T-Z].
Replace QT_FORWARD_DECLARE_CLASS with QT_BEGIN_NAMESPACE and
QT_END_NAMESPACE and forward declare inside.
Change-Id: I4ac3a8391e6167aa2db3973a9f94a45ac3c8ebd1
Reviewed-by: hjk <hjk@qt.io>