Move biochemistry related files to a new biochemistry folder

src/CMakeLists.txt

src/libaevol/CMakeLists.txt

src/libaevol/biochemistry/Alignment.cpp

src/libaevol/biochemistry/Alignment.h

src/libaevol/biochemistry/Codon.cpp

src/libaevol/biochemistry/Codon.h

src/libaevol/biochemistry/Dna.cpp

src/libaevol/biochemistry/Dna.h

src/libaevol/biochemistry/DnaReplicationReport.cpp

src/libaevol/biochemistry/DnaReplicationReport.h

src/libaevol/biochemistry/Dna_SIMD.cpp

src/libaevol/biochemistry/Dna_SIMD.h

src/libaevol/biochemistry/GeneticUnit.cpp

src/libaevol/biochemistry/GeneticUnit.h

src/libaevol/biochemistry/Protein.cpp

src/libaevol/biochemistry/Protein.h

src/libaevol/biochemistry/Rna.cpp

src/libaevol/biochemistry/Rna.h

src/libaevol/biochemistry/VisAVis.cpp

src/libaevol/biochemistry/VisAVis.h