RTSP support

[rmichelena]

Hi, adding RTSP support shouldn't be too hard and would allow for more flexible physical installations, e.g. zoom cameras to be able to be farther away or smaller packages transmitting by wifi to the processor.
In my case, repurposing a Wyze v2 camera which has excellent performance and optional RTSP firmware.

[aweussom]

Since this is written in Python, it is fairly simple to read RTSP with OpenCV and create a video feed for rpi-urban-mobility-tracker?

I used this as a starting point; Works just fine:
https://lindevs.com/capture-rtsp-stream-from-ip-camera-using-opencv/