Fix cert-manager example

This was not using the namespace that is used consistently across
the examples, which could cause confusion. Adjusted some of the
defaults to work more nicely in base installs.

Author: Jonathan S. Katz

kustomize/certmanager/postgres/kustomization.yaml

@@ -1,6 +1,6 @@
-namespace: zoo
+namespace: postgres-operator
 
 resources:
 - cert.yaml
 - cert-repl.yaml
-- postgres.yaml
+- postgres.yaml

kustomize/certmanager/postgres/postgres.yaml

@@ -5,7 +5,6 @@ metadata:
 spec:
   image: registry.developers.crunchydata.com/crunchydata/crunchy-postgres-ha:centos8-13.3-0
   postgresVersion: 13
-  openshift: true
   customReplicationTLSSecret:
     name: hippo-repl-tls
   customTLSSecret: