User repository (#3795)

* It builds with the new user repository

* fix(test): fix broken test

* fix(api): fix registration endpoint that was broken after the change

* fix(test): update test to reflect new user repository

* fix: use interface type instead of concrete type

* fix: restore commented out code

test/automated/api/003_chat.test.js

@@ -53,7 +53,6 @@ test('overwrite user header derived display name with body', async (done) => {
 	const res = await request
 		.post('/api/chat/register')
 		.send({ displayName: 'TestUserChat' })
-		.set('X-Forwarded-User', 'test-user')
 		.expect(200);
 
 	expect(res.body.displayName).toBe('TestUserChat');