Enhance Sign In / Sign Up UX

[Sallaa]

Sign In / Sign Up flow is hard to understand for users. We should simplify the UX:

• Instead of "Advanced Tools" title, the title should be "Log In" or similar
• "Access to advanced tools is reserved for journalists, fact-checkers and researchers. You need to apply and register to use them." should be on the registration page, not the login page.
• "Do you already have a code Click here" add a question mark, and the next page should not say "Your access code request has been sent successfully. If your account is valid, you should receive your access code by email in a few minutes."
• Some steps are not allowing to go back to the previous step
• "Not already registered? Register for an access to the service" can be simplified to "New User?". Register should be "Sign Up"
• The Login button should not show a big log out button but rather an avatar. This is linked to UX/UI Enhancements #467
• There should be a close button to close and exit the pop-up on all screens

We should make it easy to understand that the application is or will be under review.

It could also be useful to have a screen for when the user applied but still have their applications under review.