Reduce OpenCV dependencies

applications/calibration-multi/src/main.cpp

applications/gui/src/camera.cpp

applications/gui/src/gltexture.hpp

applications/reconstruct/src/main.cpp

applications/vision/include/ftl/streamer.hpp

components/codecs/include/ftl/codecs/decoder.hpp

components/codecs/include/ftl/codecs/encoder.hpp

components/codecs/src/opencv_decoder.cpp

components/codecs/src/opencv_encoder.cpp

components/codecs/test/nvpipe_codec_unit.cpp

components/codecs/test/opencv_codec_unit.cpp

components/operators/include/ftl/operators/disparity.hpp

components/operators/src/colours.cpp

components/operators/src/disparity/fixstars_sgm.cpp

components/operators/src/nvopticalflow.cpp

components/operators/src/smoothing.cpp

components/renderers/cpp/src/tri_render.cpp

components/rgbd-sources/CMakeLists.txt

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

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