Improve transport connection errors (#4540)

## Issue Addressed

#4538 

## Proposed Changes

add newtype wrapper around DialError that extracts error messages and logs them in a more readable format

## Additional Info

I was able to test Transport Dial Errors in the situation where a libp2p instance attempts to ping a nonexistent peer. That error message should look something like

`A transport level error has ocurred: Connection refused (os error 61)`

AgeManning mentioned we should try fetching only the most inner error (in situations where theres a nested error). I took a stab at implementing that

For non transport DialErrors, I wrote out the error messages explicitly (as per the docs). Could potentially clean things up here if thats not necessary


Co-authored-by: Age Manning <Age@AgeManning.com>

beacon_node/lighthouse_network/src/peer_manager/network_behaviour.rs

@@ -12,9 +12,9 @@ use libp2p::swarm::{ConnectionId, NetworkBehaviour, PollParameters, ToSwarm};
 use slog::{debug, error};
 use types::EthSpec;
 
-use crate::metrics;
 use crate::rpc::GoodbyeReason;
 use crate::types::SyncState;
+use crate::{metrics, ClearDialError};
 
 use super::peerdb::BanResult;
 use super::{ConnectingType, PeerManager, PeerManagerEvent, ReportSource};
@@ -132,7 +132,7 @@ impl<TSpec: EthSpec> NetworkBehaviour for PeerManager<TSpec> {
                 error,
                 connection_id: _,
             }) => {
-                debug!(self.log, "Failed to dial peer"; "peer_id"=> ?peer_id, "error" => %error);
+                debug!(self.log, "Failed to dial peer"; "peer_id"=> ?peer_id, "error" => %ClearDialError(error));
                 self.on_dial_failure(peer_id);
             }
             FromSwarm::ExternalAddrConfirmed(_) => {