bug(Auth): set expiry on token for auth/login endpoint

- refactor jwt signing into separate function
- remove unused imports

[Delivers 159728693]

server/controllers/userController.js

@@ -1,6 +1,5 @@
 import { validationResult } from 'express-validator/check';
 import bcrypt from 'bcrypt';
-import jwt from 'jsonwebtoken';
 import { query } from '../db/index';
 import queries from '../db/queries';
 import signAuthToken from '../utils/signAuthToken';