feat: Implement Dataset Selection Page and Enhance Security
requested to merge main into 21-as-a-user-i-would-like-to-be-able-to-view-the-number-used-of-each-heating-method-per-region-and
- Added a new dataset selection page for improved user navigation.
- Integrated upload forms on each individual page for streamlined data handling.
- Enhanced security measures for all admin pages to ensure data integrity and confidentiality.