Implement RTSP streaming functionality for cameras

- Added endpoints to start and stop RTSP streaming for cameras in the API.
- Enhanced CameraManager and CameraStreamer classes to manage RTSP streaming state and processes.
- Updated API documentation to include new RTSP streaming commands.
- Modified Docker configurations to include FFmpeg for RTSP streaming support.
- Adjusted MediaMTX settings for improved stream handling and timeout configurations.

mediamtx.yml

@@ -9,6 +9,11 @@ paths:
     # allow any path to be read; publishers can be added on-demand
     readUser: any
     sourceOnDemand: no
+    sourceOnDemandStartTimeout: 10s
+    sourceOnDemandCloseAfter: 10s
+    # Keep source alive even without readers (remove timeout)
+    # sourceCloseAfter: never  # Keep stream alive indefinitely
+    sourceCloseAfter: 30s  # Keep stream alive for 30 seconds after last reader disconnects
 
 # Example on-demand publisher for a demo VOD (adjust file path):
 #  vod: