routerrpc: create pair data proto message

With a separate proto message, it becomes possible to also return the
pair data for a single pair. This prepares for the new mc probability
querying rpc.

cmd/lncli/cmd_query_mission_control.go

@@ -48,9 +48,9 @@ func queryMissionControl(ctx *cli.Context) error {
 			displayPairHistory{
 				NodeFrom:              hex.EncodeToString(n.NodeFrom),
 				NodeTo:                hex.EncodeToString(n.NodeTo),
-				LastAttemptSuccessful: n.LastAttemptSuccessful,
-				Timestamp:             n.Timestamp,
-				MinPenalizeAmtSat:     n.MinPenalizeAmtSat,
+				LastAttemptSuccessful: n.History.LastAttemptSuccessful,
+				Timestamp:             n.History.Timestamp,
+				MinPenalizeAmtSat:     n.History.MinPenalizeAmtSat,
 			},
 		)
 	}