lnrpc: Deprecate fee field in payment struct

rpcserver.go

@@ -4203,6 +4203,8 @@ func (r *rpcServer) ListPayments(ctx context.Context,
 			CreationDate:    payment.Info.CreationDate.Unix(),
 			Path:            path,
 			Fee:             int64(route.TotalFees().ToSatoshis()),
+			FeeSat:          int64(route.TotalFees().ToSatoshis()),
+			FeeMsat:         int64(route.TotalFees()),
 			PaymentPreimage: hex.EncodeToString(preimage[:]),
 			PaymentRequest:  string(payment.Info.PaymentRequest),
 			Status:          status,