remove nat module and use libp2p upnp (#4840)

* remove nat module and use libp2p upnp

* update Cargo.lock

* remove no longer used dependencies

* restore nat module refactored

* log successful mapping

* only activate upnp if config enabled

reduce logs to debug!

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into libp2p-nat

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into libp2p-nat

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into libp2p-nat

* address review

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into libp2p-nat

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into libp2p-nat

* Merge branch 'unstable' of https://github.com/sigp/lighthouse into libp2p-nat

* address review

beacon_node/lighthouse_network/src/service/behaviour.rs

@@ -6,6 +6,7 @@ use crate::types::SnappyTransform;
 use crate::gossipsub;
 use libp2p::identify;
 use libp2p::swarm::NetworkBehaviour;
+use libp2p::upnp::tokio::Behaviour as Upnp;
 use types::EthSpec;
 
 use super::api_types::RequestId;
@@ -32,6 +33,8 @@ where
     // NOTE: The id protocol is used for initial interop. This will be removed by mainnet.
     /// Provides IP addresses and peer information.
     pub identify: identify::Behaviour,
+    /// Libp2p UPnP port mapping.
+    pub upnp: Upnp,
     /// The routing pub-sub mechanism for eth2.
     pub gossipsub: Gossipsub,
 }