New Features:
- Introduce the host app registry. This interface allows host system apps
(i.e. apps not running under a sandboxing mechanism like Flatpak) register
themselves with XDG Desktop Portal. This allows XDG Desktop Portal to use
a proper app id, and desktop file, improving the interaction with portal
backends.
Enhancements:
- Use a new internal script to simplify running tests.
Bug Fixes:
- Properly escape notification body in the Notification portal.
- Fix various documentation links in the USB portal documentation page.