Fix redirect not working after login

Redirecting post-login for login-overlay.tsx relies on the rd query parameter to be set. This is correctly done when clicking on a category card from the homepage (when unauthorized), but is not done when accessing a different URL directly (such as /faq or any documents), since the login form is displayed with the same URL as the target destination.

This MR changes it so that if you are not logged in, direct resource access (i.e. any page routed with UserRoute) will redirect to /login/ with the rd parameter set, thereby correctly activating the redirect post-login.

The MR also introduces a feature where if you refresh a login page after you logged in from another tab, you would be redirected properly to the target destination.