add support for configurable replication MRF workers (#12125)

just like replication workers, allow failed replication
workers to be configurable in situations like DR failures
etc to catch up on replication sooner when DR is back
online.

Signed-off-by: Harshavardhana <harsha@minio.io>

cmd/config/api/help.go

@@ -52,5 +52,11 @@ var (
 			Optional:    true,
 			Type:        "number",
 		},
+		config.HelpKV{
+			Key:         apiReplicationFailedWorkers,
+			Description: `set the number of replication workers for recently failed replicas, defaults to 4`,
+			Optional:    true,
+			Type:        "number",
+		},
 	}
 )