[Feature Requests] Allow folders in folders

[Lancelotbronner]

I'd like to categorize my feeds in a hierarchy:

• News
  • Local
  • International
• Developer
  • Swift
    • many feeds...
  • Swift Community
    • even more feeds...
  • Rust
    • etc.
  • Rust Community
• Tabletop
  • Dungeons & Dragons
  • Pathfinder
  • VTTs

The main objective here is to be able to get an "all unread" that ignores News when I get overwhelmed.

Categorizing feeds by tags could be even more powerful, saving "Collections" which would be queries based on tags.

[sashkab]

Duplicate of #4037?