Add Object Hunting example documentation

[91volt]

Summary

This PR adds the documentation for the Object Hunting example and applies necessary license header fixes to other files.

The Object Hunting example demonstrates how to use the video_objectdetection Brick to create an interactive scavenger hunt game. It streams video from a USB webcam, runs the YoloX Nano model for real-time inference, and uses a web interface to track found objects.

What changed

• Added README.md for Object Hunting:
  • Detailed the game mechanics (finding 5 specific objects).
  • Documented the hardware requirements, emphasizing the need for a powered USB-C hub and USB webcam.
  • Explained the data flow between the USB camera, the inference engine, and the Web UI.
  • Added a "How it Works" section with code snippets for both the Python backend and JavaScript frontend.
  • Included a customization guide explaining how to swap target objects using the COCO dataset.
  • Added a troubleshooting section for common issues.
• License Compliance:
  • Added SPDX license headers to needed code files to pass repository compliance checks.