bind-internal: add s3.ceph.unkin.net CNAME -> radosgw.service.consul (#265)

## Why

Publish the RGW S3 endpoint name (`s3.ceph.unkin.net`) that cephrgw-operator consumers use and that the radosgw hosts will carry as a cert SAN. For now it points at the Consul service; the real target will be changed later.

## Changes

- Add a `DNSRecord` in the `ceph.unkin.net` authoritative zone: `s3` CNAME `radosgw.service.consul.` (`apps/base/bind-internal/authoritative/records.yaml`, zoneRef `ceph-unkin-net`, TTL 600).

A companion puppet-prod change adds `s3.ceph.unkin.net` to the radosgw cert SANs and nginx server names.

---------

Co-authored-by: benvin <neotheo@gmail.com>
Reviewed-on: #265
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

apps/base/bind-internal/authoritative/records.yaml

@@ -19,3 +19,18 @@ spec:
     # traefik-internal gateway VIP; the authentik Gateway serves the
     # identity.unkin.net hostname there.
     - 198.18.200.4
+---
+apiVersion: bind.unkin.net/v1alpha1
+kind: DNSRecord
+metadata:
+  name: s3-ceph-cname
+  namespace: bind-internal
+spec:
+  zoneRef: ceph-unkin-net
+  name: s3
+  type: CNAME
+  ttl: 600
+  values:
+    # radosgw S3 endpoint. Points at the Consul service for now; the real
+    # target will be changed later.
+    - radosgw.service.consul.