Allow upload of boolean values

[kadrlica]

Numpy/FITS has a boolean data type but Oracle does not. We should still be able to upload boolean data, maybe casting it to NUMBER(1). What is the "correct" thing to do with booleans in Oracle is a topic of discussion on Stack Overflow...

[kadrlica]

DB_TYPE_BOOLEAN is available in Oracle 12.1 and higher:
https://cx-oracle.readthedocs.io/en/latest/api_manual/module.html#cx_Oracle.DB_TYPE_BOOLEAN