Add some simple accessors needed in NBC for the JSON-RPC service

eth/async_utils.nim

@@ -1,7 +1,7 @@
 import
   chronos, chronicles
 
-proc catchOrQuit(error: Exception) =
+proc catchOrQuit*(error: Exception) =
   if error of CatchableError:
     trace "Async operation ended with a recoverable error", err = error.msg
   else:

eth/p2p/discoveryv5/protocol.nim

@@ -68,6 +68,9 @@ proc newProtocol*(privKey: PrivateKey, db: Database,
 
   result.routingTable.init(node)
 
+func privKey*(p: Protocol): lent PrivateKey =
+  p.privateKey
+
 proc send(d: Protocol, a: Address, data: seq[byte]) =
   # debug "Sending bytes", amount = data.len, to = a
   let ta = initTAddress(a.ip, a.udpPort)