The public name servers resolve deb.sipwise.com to our public OVH IP
address 164.132.119.186, while internally we want to use its cname
haproxy.mgm.sipwise.com. This only works with using our internal
nameservers (like 192.168.212.30 and 192.168.88.20).
Default to 192.168.212.30, so deployments work as expected, otherwise
we're failing during deployment with:
| Err:5 https://deb.sipwise.com/autobuild release-trunk-bookworm InRelease
| 403 Forbidden [IP: 164.132.119.186 443]
While at it also update the ip=... kernel option, to use
168.192.91.XX/24 by default, and also use a FQDN for the hostname (since
that's our current policy for puppet hostname/certificates).
Change-Id: I1ce6541f7a31baa437e679b67056bb7851b1b33d