* swiftui:
Register AppDefaults. Issue #2190
Removed obsolete AppDefaults values
Revert to using List for timeline and use infinite scrolling technique to speed up timeline loads
Add action sheet for adding feed resources
Stub out Article code
Delete dead code
Fix bad merge where we were missing a file reference
# Conflicts:
# NetNewsWire.xcodeproj/project.pbxproj
This commit makes some assumptions:
- `AppSettings` is an `ObservableObject` that uses `@AppStorage` where possible, which sets default values.
- Each change to an property triggers an `objectWillChange.send()` call.
- `IconSize` is not used. Instead, it defaults to 40.0 with minimums and maximums of 20.0 and 60.0, controlled via Timeline settings.
