Login and user access to pages.

This merge request introduces role-based access control across multiple pages. On the Professor page, admins can edit and delete all professors, while individual professors can only manage their own information. On the Subjects and Rooms pages, only admins are allowed to edit or delete entries. On the Users page, admins can edit and delete all users, whereas regular users are restricted to editing or deleting only their own accounts. These changes improve security and ensure proper access control throughout the system.