dring/call: send video codec to client

src/call.h

src/client/configurationmanager.cpp

src/dring/call_const.h

src/media/audio/audio_sender.cpp

src/media/media_encoder.cpp

src/media/media_encoder.h

src/media/rtp_session.h

src/media/video/video_rtp_session.cpp

src/media/video/video_rtp_session.h

src/media/video/video_sender.cpp

src/media/video/video_sender.h

src/sip/sipcall.cpp

src/sip/sipcall.h