feat(camera): add external camera streaming with tests and ci-cd

[charlesmadjeri]

External USB Camera Streaming with Client-Based Control

Overview

This PR adds refactored support for external USB webcam streaming with automatic load reduction when no clients are connected to the control panel.

Features

• External USB Webcam Support: Added ext_camera node with robust device detection using v4l2-ctl
• Service-Based Control: Implemented start/stop streaming services for manual and automatic control
• Client Count Monitoring: Automatic streaming control based on web panel client connections
• Optimized Streaming: GStreamer pipeline optimized for 1920x1080@30fps
• Unit Tests: Comprehensive pytest unit tests with mocking for hardware-independent testing
• CI/CD Pipeline: GitHub Actions workflow for automated linting and testing
• Code Coverage: Test coverage reporting with pytest-cov

Changes

• Renamed camera from mobius to ext_camera for consistency
• Moved to camera_stream_controller.py automatic client count monitoring
• Improved camera detection with vendor/product ID matching
• (re)Integrated camera launch into lucy.launch.py
• Updated system scripts for camera management
• Fixed all linting errors across Python and launch files

Related

• Frontend changes in web_control_panel repository

[Arcod7]

LGTM
This PR is too big for me to test everything in details but it seems right