Implements #125 second RGB channel

applications/gui/src/camera.cpp

applications/gui/src/camera.hpp

applications/gui/src/media_panel.cpp

applications/gui/src/media_panel.hpp

applications/gui/src/screen.cpp

applications/gui/src/screen.hpp

components/rgbd-sources/include/ftl/rgbd/source.hpp

components/rgbd-sources/include/ftl/rgbd/streamer.hpp

components/rgbd-sources/src/net.cpp

components/rgbd-sources/src/net.hpp

components/rgbd-sources/src/source.cpp

components/rgbd-sources/src/stereovideo.cpp

components/rgbd-sources/src/streamer.cpp