Initial bind-operator: 9 CRDs + controllers

Implements a Kubernetes operator that manages fleets of BIND9 servers
declaratively, using controller-runtime (matching forgebot conventions).

- add BindCluster reconciler: StatefulSet (pod-0 primary, secondaries),
  headless + client Services, rendered named.conf ConfigMap, TSIG keys
  Secret and rndc control Secret; watches dependent CRs to re-render
- add BindTSIGKey reconciler that generates key material into a Secret
- add BindZone/DNSRecord reconcilers using fully-dynamic delivery
  (rndc addzone + TSIG nsupdate against the primary pod)
- add BindCatalogZone reconciler so secondaries auto-provision zones
- add BindPolicy (RPZ), BindDNSSECPolicy, BindView, BindACL reconcilers
- render primary/secondary named.conf variants selected by pod ordinal
- generate CRDs, deepcopy and RBAC; add samples mapping the three Puppet
  roles (authoritative/resolver/external-dns) to three BindClusters
- add Makefile, Dockerfile.operator, Woodpecker CI and kind manifests

.woodpecker/docker.yaml

@@ -0,0 +1,17 @@
+when:
+  - event: tag
+    ref: refs/tags/v*
+
+steps:
+  - name: docker-operator
+    image: woodpeckerci/plugin-docker-buildx
+    settings:
+      registry: git.unkin.net
+      repo: git.unkin.net/unkin/bind-operator
+      dockerfile: Dockerfile.operator
+      username: droneci
+      password:
+        from_secret: DRONECI_PASSWORD
+      tags:
+        - ${CI_COMMIT_TAG}
+        - latest