Removes QGL paths in sub-attaq and chip examples.
The boxes example depended on QGL and has been removed.
The corresponding module and test directories for the opengl module are now
empty, but has been left there so we can move the QOpenGL* classes there.
[ChangeLog][QtOpenGL] The deprecated QGL* classes have been removed.
Fixes: QTBUG-74408
Change-Id: I52f56409af8f6901359462a7ba162103d051fe3d
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>