Add Docker support and consolidate documentation

- Add docker-compose.yml and docker_run.sh for Raspberry Pi / Debian
- Consolidate all documentation into single comprehensive README.md
- Remove redundant markdown files (MY_ROBOT_README, RASPBERRY_PI_SETUP, DEBIAN_INSTALL)
- Add Raspberry Pi installation section following official ROS 2 recommendations
- Include custom robot quick start in main README
- Add table of contents for easy navigation

Docker is the official ROS 2 approach for Raspberry Pi OS due to library
version conflicts between Debian Trixie and Ubuntu 22.04 (Jammy).

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: yconst