Publish QtWS 2017 3D Cluster Demo

Publish 3D cluster demo shown at QtWS 2017 with descriptive readme.md and screenshot in place. Repository for the demo is https://git.qt.io/public-demos/qt3dstudio and the demo should have it's own subfolder e.g. kria-cluster-3d-demo in the repository. Move the demo to this repository once it's has been verified to work with Qt 3D Studio 1.0 code and code review is done. Review that the pre-1.0 issues in the presentation project are fixed.

Also make Android APK of the demo and submit it to the demo wiki page at https://intranet.qt.io/display/QS/Sales+Demo+Tablets+and+Demos and send email about the demo to tpyssysa for review.