mod_audit: Support for adding location (GeoIP) to audit events This can be more privacy-friendly than logging full IP addresses, and also more informative to a user - IP addresses don't mean much to the average person, however if they see activity from outside their expected country, they can immediately identify suspicious activity. As with IPs, this field is configurable for deployments that would like to disable it. Location is also not logged when the geoip library is not available.

Generate a DNS UPDATE order in format suitable for `nsupdate` based on
current port configuration.

Example output:

```
$ prosodyctl mod_dnsupdate -d example.com -t xmpp.example.com example.com
zone example.com
server ns1.example.com
ttl 3600
add _xmpp-client._tcp.example.com IN SRV 1 1 5222
add _xmpp-server._tcp.example.com IN SRV 1 1 5269
```