Fixed ConstView for segments and deleted duplicit code in ChunkedEllpack.

src/TNL/Containers/Segments/CSR.h

src/TNL/Containers/Segments/CSR.hpp

src/TNL/Containers/Segments/CSRView.h

src/TNL/Containers/Segments/CSRView.hpp

src/TNL/Containers/Segments/ChunkedEllpack.h

src/TNL/Containers/Segments/ChunkedEllpack.hpp

src/TNL/Containers/Segments/ChunkedEllpackView.h

src/TNL/Containers/Segments/ChunkedEllpackView.hpp

src/TNL/Containers/Segments/Ellpack.h

src/TNL/Containers/Segments/Ellpack.hpp

src/TNL/Containers/Segments/EllpackView.h

src/TNL/Containers/Segments/EllpackView.hpp

src/TNL/Containers/Segments/SlicedEllpack.h

src/TNL/Containers/Segments/SlicedEllpack.hpp

src/TNL/Containers/Segments/SlicedEllpackView.h

src/TNL/Containers/Segments/SlicedEllpackView.hpp

src/UnitTests/Containers/Segments/SegmentsTest.hpp