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/handler.rs

@@ -283,8 +283,8 @@ where
         let inbound_info = if let Some(info) = self.inbound_substreams.get_mut(&inbound_id) {
             info
         } else {
-            warn!(self.log, "Stream has expired. Response not sent";
-                "response" => response.to_string(), "id" => inbound_id);
+            warn!(self.log, "Inbound stream has expired, response not sent";
+                "response" => response.to_string(), "id" => inbound_id, "msg" => "Likely too many resources, reduce peer count");
             return;
         };
 

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(),