migrate to "export default"

also, set no-use-before-define in linter

src/iputils.js

@@ -1,9 +1,5 @@
 import assert from 'node:assert';
 
-export {
-    ipFromInt,
-    intFromIp
-};
 
 // this code is used in migrations - 20201120212726-apps-add-containerIp.js
 function intFromIp(address) {
@@ -33,3 +29,7 @@ function ipFromInt(input) {
     return output.join('.');
 }
 
+export default {
+    ipFromInt,
+    intFromIp
+};