Update Copyright statement to include 2024

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doc/mainpage.h

source/App/BitstreamExtractorApp/BitstreamExtractorApp.cpp

source/App/BitstreamExtractorApp/BitstreamExtractorApp.h

...ce/App/BitstreamExtractorApp/BitstreamExtractorAppCfg.cpp

source/App/BitstreamExtractorApp/BitstreamExtractorAppCfg.h

source/App/BitstreamExtractorApp/bitstreamextractormain.cpp

source/App/DecoderApp/DecApp.cpp

source/App/DecoderApp/DecApp.h

source/App/DecoderApp/DecAppCfg.cpp

source/App/DecoderApp/DecAppCfg.h

source/App/DecoderApp/decmain.cpp

source/App/EncoderApp/EncApp.cpp

source/App/EncoderApp/EncApp.h

source/App/EncoderApp/EncAppCfg.cpp

source/App/EncoderApp/EncAppCfg.h

source/App/EncoderApp/encmain.cpp

source/App/Parcat/parcat.cpp

source/App/SEIFilmGrainApp/SEIFilmGrainApp.cpp

source/App/SEIFilmGrainApp/SEIFilmGrainApp.h