Implements parsing, scoring, CLI output, and UI display for the DMARC
np= tag (DMARCbis draft-ietf-dmarc-dmarcbis), which controls policy for
NXDOMAIN subdomains independently of sp=. The score deducts 15 points
from the base and awards them back when np= is absent (good default) or
its strength is equal to or stricter than the effective sp=/p= policy.
