Add Patroni failsafe_mode parameter (#2076)

This commit adds support of a not-yet-released Patroni feature that allows postgres to run as primary in case of a failed leader lock update.
* Add Patroni 'failsafe_mode' local parameter (enable for a single PG cluster)
* Allow configuring Patroni 'failsafe_mode' parameter globally

charts/postgres-operator/crds/operatorconfigurations.yaml

@@ -633,6 +633,12 @@ spec:
                     type: string
                     pattern: '^(\d+(e\d+)?|\d+(\.\d+)?(e\d+)?[EPTGMK]i?)$'
                     default: "100Mi"
+              patroni:
+                type: object
+                properties:
+                  failsafe_mode:
+                    type: boolean
+                    default: false
           status:
             type: object
             additionalProperties:

charts/postgres-operator/crds/postgresqls.yaml

@@ -320,6 +320,8 @@ spec:
               patroni:
                 type: object
                 properties:
+                  failsafe_mode:
+                    type: boolean
                   initdb:
                     type: object
                     additionalProperties:

charts/postgres-operator/values.yaml

@@ -409,6 +409,10 @@ configConnectionPooler:
   connection_pooler_default_cpu_limit: "1"
   connection_pooler_default_memory_limit: 100Mi
 
+configPatroni:
+  # enable Patroni DCS failsafe_mode feature
+  failsafe_mode: false
+
 # Zalando's internal CDC stream feature
 enableStreams: false