Upgrade UI for Site Login Component Popup

Upgrade the UI for the Site login Component Popup in site_login_component.tsx. Upgrades include:

1. Move the popup to the side of the window.
2. The input field for the simple passphrase should be a password input with *'s.
3. The popup should disappear when the password has been calculated and entered into the login field.
4. Make the text, buttons, and popup look clean and not default.