refactor: Use ESM (#8358)

* wip

* wip

* fix

* clean up

* Update tsconfig.json

* Update activitypub.ts

* wip

packages/backend/test/user-notes.ts

@@ -2,7 +2,7 @@ process.env.NODE_ENV = 'test';
 
 import * as assert from 'assert';
 import * as childProcess from 'child_process';
-import { async, signup, request, post, uploadFile, startServer, shutdownServer } from './utils';
+import { async, signup, request, post, uploadFile, startServer, shutdownServer } from './utils.js';
 
 describe('users/notes', () => {
 	let p: childProcess.ChildProcess;