Add OpenGLInfo attached type

[ChangeLog][QtQuick] Introduced OpenGLInfo attached type that
provides information about the currently used OpenGL version.

Change-Id: Ibdf365decf9d6331cf91c0bf541e493ced02a417
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>