Deploy bind-operator (operator + CRDs)

Deploys the bind-operator control plane on its own so it can be verified
before any DNS clusters are created. The three BIND tiers follow as
separate PRs.

- add apps/base/bind-system: operator Deployment (image v0.1.1), RBAC,
  namespace, and CRDs pulled from the operator repo by raw URL
- add au-syd1 bind-system overlay
- register all four bind apps in the platform ApplicationSet (the DNS
  overlays are instantiated only once their dirs land in later PRs)
- add binddns-* namespaces to the platform AppProject destinations
- add schemas/bind.unkin.net/*.json so kubeconform validates the CRs

argocd/applicationsets/platform.yaml

@@ -12,6 +12,10 @@ spec:
       directories:
       - path: apps/overlays/*/authentik
       - path: apps/overlays/*/artifactapi
+      - path: apps/overlays/*/bind-system
+      - path: apps/overlays/*/binddns-auth
+      - path: apps/overlays/*/binddns-resolver
+      - path: apps/overlays/*/binddns-externaldns
       - path: apps/overlays/*/age-api
       - path: apps/overlays/*/cattle-system
       - path: apps/overlays/*/cert-manager