Improve Login page layout

[benoror]

• [ ] Anchor to the top
• [ ] Make it smaller
• [ ] Move "Don't have an account? ..." section outside paper

Example

Demo: https://material-ui.com/getting-started/page-layout-examples/sign-in/

Code: https://github.com/mui-org/material-ui/tree/master/docs/src/pages/getting-started/page-layout-examples/sign-in