deploy encapi to au-syd1

encapi is the new Postgres-backed Puppet ENC replacing Cobbler. Stand it up in
k8s alongside artifactapi so the puppet masters (via encapi-cli classify) and
the enc_direct_facts fact can reach it at encapi.k8s.syd1.au.unkin.net.

- add apps/base/encapi: namespace, deployment (git.unkin.net/unkin/encapi), service,
  gateway + httproute (encapi.k8s.syd1.au.unkin.net), configmap, CNPG cluster +
  pooler (db encapi), VaultAuth + VaultStaticSecrets (postgres-credentials, environment)
- add apps/overlays/au-syd1/encapi overlay
- register apps/overlays/*/encapi in the platform ApplicationSet

Note: the Vault KV secrets kv/kubernetes/namespace/encapi/default/{postgres-credentials,
environment} must be seeded before first sync; 'environment' carries DBPASS (matching
the CNPG owner password) and ENCAPI_WRITE_TOKEN.

apps/base/encapi/service.yaml

@@ -0,0 +1,17 @@
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: encapi
+  namespace: encapi
+spec:
+  internalTrafficPolicy: Cluster
+  ports:
+    - name: http
+      port: 80
+      protocol: TCP
+      targetPort: http
+  selector:
+    app: encapi
+  sessionAffinity: None
+  type: ClusterIP