Download data/model for tutorials and examples from qt.io

Download data/model for tutorials and examples from qt.io

We would create a folder containing the models for examples and tutorials.
The .zip file would be downloaded and include all the necessary data and thumbnails.

To decide"Do we provide default data in case the internet is down"? I suggest not, since without internet you cannot access the examples/tutorials.

This will allow adjusting thumbnails, adding, and removing examples and tutorials at any time.