Make username and password persist over renders

[ecumene]

• [x] make username state
• [x] make password state

[JPM709]

user information is now in useState:

const [userInformation, setUserInformation] = useState({
    username: "",
    password: "",
  });

onChange functions now use setUserInformation:

 const onChangeName = (event) => {
    setUserInformation((prevState) => ({
      username: event.target.value,
      password: prevState.password,
    }));
  };
  const onChangePassword = (event) => {
    setUserInformation((prevState) => ({
      username: prevState.username,
      password: event.target.value,
    }));
  };