feat(postgres): Tighten network policy for postgres-operator

This patch thightens up the network policy that is deployed to all
namespaces, to limit access to the postgres-operator managed pods.

infrastructure/postgres/user-namespace-network-policy.yaml

@@ -20,6 +20,15 @@ spec:
             - namespaceSelector:
                 matchLabels:
                   name: zalando-postgres
-          podSelector: {}
+          podSelector:
+            matchLabels:
+              application: spilo
           policyTypes:
           - Ingress
+          ports:
+          - containerPort: 8008
+            protocol: TCP
+          - containerPort: 5432
+            protocol: TCP
+          - containerPort: 8080
+            protocol: TCP