3rd party asset license information missing from Qt3D examples

glTF example assets are taken from:
https://github.com/KhronosGroup/glTF/tree/master/model/wine
Should contain approrpiate license information:
https://github.com/KhronosGroup/glTF/blob/master/LICENSE.md

Same applies for all the other material under exampleresources/assets.

Appropriate copyright and license information should be added to all of the subfolders.