Add point cloud rendering example

## What problem does this solve or what need does it fill?
Like Gizmos and Wireframes, point cloud rendering is useful for debugging purposes and prototyping.
Moreover some types of data might require point cloud rendering for visualization, including but not limited to:
- Photogrammetry data
- Scientific & Statistics data

Review the existing Gizmos and Wireframes rendering examples mentioned in the issue, along with the repository's example conventions. Determine the entry point and validation approach for a point cloud rendering example. Done means the example demonstrates point cloud visualization for debugging, prototyping, or the listed data types.

Written by the indexing model from the issue text.