[core] First user login checks are not displayed

1. Start with a fresh DB
2. Open the login page and see the "Since this is your first time logging in, pick any username and password. Be sure to remember these, as they will become your Hue superuser credentials."
3. Enter a username with a space or no password
4. Try to login

We don't display the error message anymore.
"This value may contain only letters, numbers and @/./+/-/_ characters"
and maybe "missing password"

Note: how about moving the trademark line to the very bottom?