Add option to show/hide your password in Login and Registration

[agnes97]

Based on: https://dev.to/detoner777/show-hide-password-on-toggle-in-react-hooks-1lph

[agnes97]

 const togglePasswordVisiblity = () => {
    setPasswordShown(passwordShown ? false : true);
  };

Can be refactored to:

 const togglePasswordVisiblity = () => {
    setPasswordShown(!setPasswordShown);
  };