Use /status subresource instead of plain manifest field (#534)

* turns PostgresStatus type into a struct with field PostgresClusterStatus
* setStatus patch target is now /status subresource
* unmarshalling PostgresStatus takes care of previous status field convention
* new simple bool functions status.Running(), status.Creating()

manifests/operator-service-account-rbac.yaml

@@ -14,6 +14,7 @@ rules:
   - acid.zalan.do
   resources:
   - postgresqls
+  - postgresqls/status
   - operatorconfigurations
   verbs:
   - "*"
@@ -137,7 +138,7 @@ rules:
   - clusterroles
   verbs:
   - bind
-  resourceNames: 
+  resourceNames:
   - zalando-postgres-operator
 
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