Silky smooth discovery (#1274)

* Initial structural re-write

* Improving discovery update and correcting attestation service logic

* Rework discovery.mod

* Handling lifetimes of query futures

* Discovery update first draft

* format fixes

* Stabalise discv5 update

* Formatting corrections

* Limit FindPeers queries and bug correction

* Update to stable release discv5

* Remove unnecessary pin

* formatting

beacon_node/eth2_libp2p/src/lib.rs

@@ -0,0 +1,29 @@
+/// This crate contains the main link for lighthouse to rust-libp2p. It therefore re-exports
+/// all required libp2p functionality.
+///
+/// This crate builds and manages the libp2p services required by the beacon node.
+#[macro_use]
+extern crate lazy_static;
+
+pub mod behaviour;
+mod config;
+mod metrics;
+mod peer_manager;
+pub mod rpc;
+mod service;
+pub mod types;
+
+pub use crate::types::{error, Enr, GossipTopic, NetworkGlobals, PubsubMessage};
+pub use behaviour::{BehaviourEvent, PeerRequestId, Request, Response};
+pub use config::Config as NetworkConfig;
+pub use discv5;
+pub use libp2p::gossipsub::{MessageId, Topic, TopicHash};
+pub use libp2p::{core::ConnectedPoint, PeerId, Swarm};
+pub use libp2p::{multiaddr, Multiaddr};
+pub use peer_manager::discovery;
+pub use peer_manager::{
+    client::Client,
+    discovery::{CombinedKeyExt, EnrExt, Eth2Enr},
+    PeerDB, PeerInfo, PeerSyncStatus, SyncInfo,
+};
+pub use service::{Libp2pEvent, Service, NETWORK_KEY_FILENAME};