define readinessProbe on statefulSet (#1825)

* define readinessProbe on statefulSet 
* do not error out on deleting Patroni cluster objects
* change delete order for patroni objects

charts/postgres-operator/templates/clusterrole-postgres-pod.yaml

@@ -9,7 +9,7 @@ metadata:
     app.kubernetes.io/managed-by: {{ .Release.Service }}
     app.kubernetes.io/instance: {{ .Release.Name }}
 rules:
-# Patroni needs to watch and manage endpoints
+# Patroni needs to watch and manage config maps or endpoints
 {{- if toString .Values.configGeneral.kubernetes_use_configmaps | eq "true" }}
 - apiGroups:
   - ""
@@ -24,12 +24,6 @@ rules:
   - patch
   - update
   - watch
-- apiGroups:
-  - ""
-  resources:
-  - endpoints
-  verbs:
-  - get
 {{- else }}
 - apiGroups:
   - ""

charts/postgres-operator/templates/clusterrole.yaml

@@ -89,12 +89,6 @@ rules:
   - patch
   - update
   - watch
-- apiGroups:
-  - ""
-  resources:
-  - endpoints
-  verbs:
-  - get
 {{- else }}
 # to read configuration from ConfigMaps
 - apiGroups: