Router config: set peers_failover_brokering to false (#341)

Author: JEnoch

rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5

@@ -157,7 +157,9 @@
       /// directly connected to it if it detects that those peers are not
       /// connected to each other.
       /// The failover brokering only works if gossip discovery is enabled.
-      peers_failover_brokering: true,
+      /// ROS setting: disabled by default because it serves no purpose when each peer connects directly to all others,
+      ///              and it introduces additional management overhead and extra messages during system startup.
+      peers_failover_brokering: false,
     },
     /// The routing strategy to use in peers and it's configuration.
     peer: {