Small network adjustments (#1884)

## Issue Addressed

- Asymmetric pings - Currently with symmetric ping intervals, lighthouse nodes race each other to ping often ending in simultaneous ping connections. This shifts the ping interval to be asymmetric based on inbound/outbound connections
- Correct inbound/outbound peer-db registering - It appears we were accounting inbound as outbound and vice versa in the peerdb, this has been corrected
- Improved logging

There is likely more to come - I'll leave this open as we investigate further testnets

beacon_node/eth2_libp2p/src/rpc/mod.rs

@@ -119,7 +119,7 @@ impl<TSpec: EthSpec> RPC<TSpec> {
                 Duration::from_secs(10),
             )
             .build()
-            .unwrap();
+            .expect("Configuration parameters are valid");
         RPC {
             limiter,
             events: Vec::new(),