Extend catz.yaml config with a bind-conf section mapping catalog names
to also-notify IP lists. Zones in catalogs with also-notify configured
get an also-notify directive in the generated domains.conf. IPs are
deduplicated and sorted when a zone belongs to multiple catalogs.
Zones without a file= property (e.g. ddns zones) are included in
catalog zone output for secondaries but skipped in domains.conf.
Previously --bind-conf required every zone to have file= set.
Generate a BIND-format domains.conf file alongside catalog zones.
New input properties: file= (zone data path) and dnssec (bare flag).
When --bind-conf is set, every zone must have file= or it errors.
Renames ZoneEntry.File to ZonesFile (input path for error messages)
and adds ZoneFile (BIND file path) and DNSSEC (bool) fields.
