Add XX mappings of Serology

[pbashyal-nmdp]

Consolidate serology tables and add Serology to XX mappings.

New serology_mapping schema:

sqlite> .schema serology_mapping
CREATE TABLE serology_mapping (
                            serology TEXT PRIMARY KEY,
                            allele_list TEXT,
                            lgx_allele_list TEXT,
                            xx TEXT NOT NULL
);