Since I can't #include qobjectdefs from qnamespace because of circular dependency,
move the Qt macro in the qtmetamacros.h header.
Deprecate QObject::staticQtMetaObject since now one can just use Qt::staticMetaObject
Change-Id: I11982aa17c2afa2067486b113f8052672f3695eb
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>