synchronous_node_count support (#1484)

* synchronous_node_count support
* notification about Patroni image version
* default synchronous_node_count to 1

Co-authored-by: Felix Kunde <felix-kunde@gmx.de>

manifests/complete-postgres-manifest.yaml

@@ -119,6 +119,7 @@ spec:
     retry_timeout: 10
     synchronous_mode: false
     synchronous_mode_strict: false
+    synchronous_node_count: 1
     maximum_lag_on_failover: 33554432
 
 # restore a Postgres DB with point-in-time-recovery

manifests/postgresql.crd.yaml

@@ -341,6 +341,8 @@ spec:
                     type: boolean
                   synchronous_mode_strict:
                     type: boolean
+                  synchronous_node_count:
+                    type: integer
                   ttl:
                     type: integer
               podAnnotations: