- add the new role to redirect.archlinux.org
- release mirror.pkgbuild.com of all DNS duties

We don't want mirror.pkgbuild.com's DNS server to be a
single-point-of-failure, so this commit adds multiple authoritative DNS
servers for the zone. The extra DNS servers are run on the geomirror
servers.

The _acme-challenge zone, used for obtaining certificates, is run solely
on mirror.pkgbuild.com's DNS server, to avoid syncing DNS records
between the servers (KISS).

The sponsored mirrors have a ton of storage, but mirror.pkgbuild.com
doesn't, so debug packages aren't synced to it.

[1] {america,asia,europe}.mirror.pkgbuild.com

This is meant as a internal authenticated and encrypted network which we
can use for internal services, we don't want to expose to the internet
or when encryption is desired but not easily implementable.

Add the ip addresses for mirror.pkgbuild.com, otherwise the apollo and archlinux.org playbooks won't run

Zabbix has been replaced by Prometheus for monitoring our services.

Signed-off-by: Florian Pritz <bluewind@xinu.at>