If the current user is a system administrator, and is not "admin", redirect to a new page where they are asked to change the user "admin"'s password.
As long as the default credentials aren't changed, or "admin" isn't deactivated, the system administrator cannot interact with the SonarQube UI in any other way.
Once performed, the user can use the SonarQube UI again.
We must update /api/navigation/global and send a new flag only for system administrators to make sure users don't type the new path manually, and get an unusable form. This new flag is called instanceUsesDefaultAdminCredentials, and returns a boolean (and will not be provided for any user that's not a system administrator).