Replace DB-IP Country Lite with IPinfo Lite (9.8.0) (#711)

Switch the bundled IP-to-country database from DB-IP Country Lite to
IPinfo Lite for greater lookup accuracy. The download URL, cached
filename, and packaged module path all move from
dbip/dbip-country-lite.mmdb to ipinfo/ipinfo_lite.mmdb.

IPinfo Lite uses a different MMDB schema (flat country_code) that is
incompatible with geoip2's Reader.country() helper, so get_ip_address_country()
now uses maxminddb directly and handles both the IPinfo schema and
the MaxMind/DBIP nested country.iso_code schema so users who drop in
their own MMDB from any of these providers continue to work.

Drop the geoip2 dependency (it was only used for the incompatible
helper) and add maxminddb as a direct dependency — it was already
installed transitively through geoip2.

Callers that imported parsedmarc.resources.dbip directly need to switch
to parsedmarc.resources.ipinfo. Old parsedmarc versions downloading
from the dbip/ GitHub raw URL will 404 and fall back to their bundled
copy — this is the documented behavior of load_ip_db().

Co-authored-by: Sean Whalen <seanthegeek@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/source/usage.md

@@ -133,7 +133,7 @@ The full set of configuration options are:
   - `forensic_json_filename` - str: filename for the forensic
       JSON output file
   - `ip_db_path` - str: An optional custom path to a MMDB file
-      from MaxMind or DBIP
+      from IPinfo, MaxMind, or DBIP
   - `ip_db_url` - str: Overrides the default download URL for the
       IP-to-country database (env var: `PARSEDMARC_GENERAL_IP_DB_URL`)
   - `offline` - bool: Do not use online queries for geolocation