Port xr_multiview_model_viewer to Android

Fix KDGpu url

Fix KDGpu url

Add grass texture to the ground plane

Improvements to XR model example

Compilation fix for gcc

Rely upon KDGpu to pull in the spdlog and fmt dependencies

Implementation of push constants for colour

Allow to toggle between horizontal and vertical movements

Introduce initial XR based example

Use ray tracing shader compilation from KDGpu

Use ray tracing shader compilation from KDGpu

Add ray tracing shader compilation function

Expand README with information on KDAB

Check spdlog dependency before kdgpu