Add Substream to rtsp on V2 and pan

NVRs need a Substream (low resolution secondary stream)to display several ip cams at once on monitor. As of now rtsp firmware only outputs to one single high res stream unlike many other simpler ip cameras on the market that have 2 streams.

Please add multiple streams functionality to v1,v2, v3, pan, etc.

#RTSP
#NVR
#Stream

Having the same issue adding several V3s to my NVR. Sub stream is required.