Visual Organization for Offers and Signup Pages in Admin Interface

Current Situation: The admin interface for Offers Settings and Signup Page management displays all items in a flat list, making it difficult to manage and navigate when you have many offers and signup pages.

Requested Feature: Add the ability to create visual folders/categories to organize offers and signup pages in the admin interface, similar to how groups can have parent-child hierarchical relationships.

Desired Functionality:

Folder/category system for organizing related offers (e.g., "Workshop Offers," "Membership Offers," "Regional Offers")

Visual hierarchy that could optionally reflect existing group structure relationships

Drag-and-drop organization for easy management

Collapsible sections to keep interface clean and manageable

Use Case Example: Instead of seeing a flat list of 15+ individual workshop offers, organize them like:

📚 Workshop Offers

├── Belgian Interpreter Workshop

├── CODA's Journey Workshop

├── Ethics Workshop

└── [other workshops]

👥 Membership Offers

├── IWC Membership

└── CPD Membership

Business Benefit: Improved admin experience and easier management of complex community monetization structures, especially for communities with multiple product lines or service categories.