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

pkg/util/config/config.go

@@ -234,6 +234,7 @@ type Config struct {
 	TargetMajorVersion                     string            `name:"target_major_version" default:"14"`
 	PatroniAPICheckInterval                time.Duration     `name:"patroni_api_check_interval" default:"1s"`
 	PatroniAPICheckTimeout                 time.Duration     `name:"patroni_api_check_timeout" default:"5s"`
+	EnablePatroniFailsafeMode              *bool             `name:"enable_patroni_failsafe_mode" default:"false"`
 }
 
 // MustMarshal marshals the config or panics