[Dev] DNS changes

[Luke Shumaker]

Howdy,

I've added DNS records for pur.parabola.nu/pur.parabolagnulinux.org.
The aurweb4 software isn't deployed there yet, but it's in the works.

While I was adding the DNS records, I noticed that
labs.parabolagnulinux.org and www.parabolagnulinux.org were both
missing SPF/TXT records, so I added those to match their parabola.nu
counterparts.

On that note, I've written a script to generate the DNS zone files.
I'd like to set up a DNS authoritative server to make maintaining the
DNS records easier, instead of using the dns.he.net web interface, but
that should probably be overseen by someone who has done it before.
The script lives in `parabola.nu:~lukeshu/dns/`, for those with SSH
(that should be everyone with git access, but adding users from
hackers.git to NSS/PAM isn't yet automated, so recently added
developers might not be in there).

-- 
Happy hacking,
~ Luke Shumaker