new command: build_ref_db to build a reference database with metadata

for the taxonomic assignment of sequences

python/obitools3/dms/dms.cfiles

@@ -1,5 +1,6 @@
 ../../../src/array_indexer.c
 ../../../src/bloom.c
+../../../src/build_reference_db.c
 ../../../src/char_str_indexer.c
 ../../../src/crc64.c
 ../../../src/dna_seq_indexer.c