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

lighthouse/environment/Cargo.toml

@@ -21,3 +21,4 @@ slog-json = "2.3.0"
 exit-future = "0.2.0"
 lazy_static = "1.4.0"
 lighthouse_metrics = { path = "../../common/lighthouse_metrics" }
+discv5 = "0.1.0-alpha.5"

lighthouse/environment/src/executor.rs

@@ -126,3 +126,9 @@ impl TaskExecutor {
         &self.log
     }
 }
+
+impl discv5::Executor for TaskExecutor {
+    fn spawn(&self, future: std::pin::Pin<Box<dyn Future<Output = ()> + Send>>) {
+        self.spawn(future, "discv5")
+    }
+}