sdp: make 1 media line per profile
sdp: make 1 media line per profile

If we have multiple profiles (AVP or AVPF) for a stream, make one m=
line in the SDP for each profile. The client is then supposed to pick
one of the profiles in the SETUP request. Because the m= lines have the
same pt, the client also knows that only 1 option is possible.

hsteinhaus/gst-rtsp-server,thaytan/gst-rtsp-server,surround-io/gst-rtsp-server,surround-io/gst-rtsp-server,barisdemiray/gst-rtsp-server,barisdemiray/gst-rtsp-server,Lachann/gst-rtsp-server,barisdemiray/gst-rtsp-server,Lachann/gst-rtsp-server,Lachann/gst-rtsp-server,hsteinhaus/gst-rtsp-server,thaytan/gst-rtsp-server,hsteinhaus/gst-rtsp-server,thaytan/gst-rtsp-server,surround-io/gst-rtsp-server