Integrates a "See on site" button in the admin change forms for `Category`, `Brand`, and `Product` models. This allows users to navigate directly to the corresponding storefront page of the object being edited, improving efficiency and user experience.
- Introduced `StorefrontLinkMixin` for reusable storefront URL logic.
- Added custom template `change_form_with_storefront_link.html` for rendering the button.
Introduce templates for admin documentation, including model details, views, template tags, filters, and bookmarklets. This enhances the admin interface by providing detailed documentation directly within the application.
