migrate to "export default"

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

src/addonconfigs.js

@@ -1,16 +1,6 @@
 import assert from 'node:assert';
-import * as database from './database.js';
+import database from './database.js';
 
-export {
-    get,
-    set,
-    unset,
-
-    getByAppId,
-    getByName,
-    unsetByAppId,
-    getAppIdByValue,
-};
 
 async function set(appId, addonId, env) {
     assert.strictEqual(typeof appId, 'string');
@@ -77,3 +67,14 @@ async function getByName(appId, addonId, namePattern) {
     if (results.length === 0) return null;
     return results[0].value;
 }
+
+export default {
+    get,
+    set,
+    unset,
+
+    getByAppId,
+    getByName,
+    unsetByAppId,
+    getAppIdByValue,
+};