Add host-record management

I've discovered that it is easier to manage DNS records using host-record so I added it.

Like the man explains:
--host-record=<name>[,<name>....][<IPv4-address>],[<IPv6-address>]
Add A, AAAA and PTR records to the DNS. This adds one or more names to the DNS with associated IPv4 (A) and IPv6 (AAAA) records. A name may appear in more than one host-record and therefore be assigned more than one address. Only the first address creates a PTR record linking the address to the name. This is the same rule as is used reading hosts-files. host-record options are considered to be read before host-files, so a name appearing there inhibits PTR-record creation if it appears in hosts-file also. Unlike hosts-files, names are not expanded, even when expand-hosts is in effect. Short and long names may appear in the same host-record, eg. --host-record=laptop,laptop.thekelleys.org,192.168.0.1,1234::100