[Feature Request] Allow the organization of favorites on ZeroHello

**Is your feature request related to a problem? Please describe.**
On ZeroHello we have some categories like Recently Downloaded, Favorites and merged. But not any way to create our own

**Describe the solution you'd like**
A way to create our own Website "Folders" like the Merged and Favorite one.

It's a simple suggestion, but idk how hard it would be to implement really.

Start by locating the ZeroHello UI for Recently Downloaded, Favorites, and merged sites, then determine how custom website folders should be created and organized. Done means users can create their own folders and place favorite websites in them; the issue provides no file or test references.

索引モデルが issue の本文から書いたものです。