feat(keycloak): Switch to HA database backend

apps/k8s01/keycloak/database-override.yaml

+apiVersion: "acid.zalan.do/v1"
+kind: postgresql
+metadata:
+  name: keycloak-postgres
+  namespace: keycloak
+spec:
+  numberOfInstances: 2

apps/k8s01/keycloak/kustomization.yaml

@@ -6,3 +6,5 @@ resources:
   - keycloak-values.yaml
   - certificate.yaml
   - ../../../shared/resourcequotas/default.yaml
+patchesStrategicMerge:
+- database-override.yaml