Add comprehensive test suite for USDA Vision Camera System

- Implemented main test script to verify system components and functionality.
- Added individual test scripts for camera exposure settings, API changes, camera recovery, maximum FPS, MQTT events, logging, and timezone functionality.
- Created service file for system management and automatic startup.
- Included detailed logging and error handling in test scripts for better diagnostics.
- Ensured compatibility with existing camera SDK and API endpoints.

tests/legacy_tests/main.py

@@ -0,0 +1,6 @@
+def main():
+    print("Hello from usda-vision-cameras!")
+
+
+if __name__ == "__main__":
+    main()