Theoretically we should be able to request a ipv6/60 with RAD. Add a comment in case this breaks randomly.

Start pulling some of the settings out and grouping them at the top as variables. We're not savages here.

Fiddle a bit with dns/dnsmasq. Avahi seems to be working better now, but the local zone can no longer be directly addressed. Naked hostnames (eg 'ping nas' or 'ping router') work fine now though.