Launcher: Coordinate and create a way to categorize / cluster / subfolderize apps in the drawer

Feature request, backed by a bounty:

• Use an existing mock-up or design your own mock-up that shows how apps in the launcher's drawer can be categorized (via XDG categories, maybe with the option to adjust things via drag'n'drop later)
• Communitate your approach to the UBports UX team and adjust your approach
• Implement the approach / design idea in QML

Examples (unknown author, for Ubuntu Touch):

See also https://www.youtube.com/watch?app=desktop&v=kdpf48f5UKo

Example 2 (from Sailfish OS):

Example (from MeeGo 1.2 Harmattan):

Example (from GNOME):