Fixes T9001
New Features:
- New Settings class to share Pantheon desktop settings with apps
- Introduced Settings.prefers_color_scheme to get a user's color scheme preference, i.e. for a dark style
Deprecations:
- It is now recommended to use GLib.Settings instead of Granite.Services.Settings
Improvements:
- Better align labels in settings sidebars
- Make AccelLabel.label settable
- Updated translations