dns: nsupdate host records to the authoritative server (#475)

Replaces the exported-resources → puppet DNS master zone-file flow with per-host RFC2136 dynamic updates against the k8s **bind-authoritative** write endpoint (198.18.200.9). The master no longer manages zone files.

## Design
Each node assembles its DNS records into a local concat file; a systemd `.path` unit watches it and runs `dns-update` (nsupdate) on change — exactly the watch-a-file model requested.

## Changes
- **profiles::dns::updater** (new): concat records file + TSIG key file + `dns-update` script + `dns-update.service` (oneshot) + `dns-update.path` (watcher). The script sends only the delta since last run and deletes removed records, grouped per zone.
- **profiles::dns::record**: writes a local concat fragment (`zone|name|type|ttl|value`) instead of exporting `@@concat::fragment` to the master.
- **profiles::dns::base**: includes `profiles::dns::updater` (all nodes).
- **hiera**: `profiles::dns::updater` server/key_name/algorithm in common.yaml.

## Inert until keyed
The updater does nothing until `profiles::dns::updater::key_secret` (TSIG) is set in eyaml — records are assembled but not applied, so nodes are safe before the key exists.

## Prerequisites (k8s side, separate)
1. The `bind-authoritative` zones must set `dynamicUpdate: true` + an `updateKeyRef` (a client-update BindTSIGKey) so they accept these updates.
2. The TSIG key must be shared: the operator-generated key value goes into eyaml here (or the planned Vault-sync feature bridges it).

## Validated
puppet parser/epp validate, puppet-lint, and a functional test of the generated per-zone nsupdate message (replace + delete-removed).

Reviewed-on: #475
Co-authored-by: Ben Vincent <ben@unkin.net>
Co-committed-by: Ben Vincent <ben@unkin.net>

hieradata/common.eyaml

@@ -6,3 +6,4 @@ profiles::consul::token::node_editor::secret_id: ENC[PKCS7,MIIBmQYJKoZIhvcNAQcDo
 profiles::consul::server::acl_tokens_initial_management: ENC[PKCS7,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]
 profiles::consul::server::acl_tokens_default: ENC[PKCS7,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]
 profiles::consul::server::acl_tokens_replication: ENC[PKCS7,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]
+profiles::dns::updater::key_secret: ENC[PKCS7,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]