ENH: fetch spectral sensitivity in optical IMIs

Modules/Core/Metadata/include/otbDimapMetadataHelper.h

...Core/Metadata/include/otbFormosatImageMetadataInterface.h

...s/Core/Metadata/include/otbIkonosImageMetadataInterface.h

...Core/Metadata/include/otbPleiadesImageMetadataInterface.h

...ore/Metadata/include/otbQuickBirdImageMetadataInterface.h

...es/Core/Metadata/include/otbSpot6ImageMetadataInterface.h

...les/Core/Metadata/include/otbSpotImageMetadataInterface.h

...re/Metadata/include/otbWorldView2ImageMetadataInterface.h

...s/Core/Metadata/src/otbFormosatImageMetadataInterface.cxx

...les/Core/Metadata/src/otbIkonosImageMetadataInterface.cxx

...es/Core/Metadata/src/otbImageMetadataInterfaceFactory.cxx

...s/Core/Metadata/src/otbPleiadesImageMetadataInterface.cxx

.../Core/Metadata/src/otbQuickBirdImageMetadataInterface.cxx

Modules/Core/Metadata/src/otbSpot6ImageMetadataInterface.cxx

Modules/Core/Metadata/src/otbSpotImageMetadataInterface.cxx

...Core/Metadata/src/otbWorldView2ImageMetadataInterface.cxx