Finish extraction

- Moves SwiftUI code out of Riot and into RiotSwiftUI which has no dependency on Matrix SDK.
- Git wasn't smart enough to see the file moves. Most feature function has remain unchanged. 1 change I did make was remove NotificationSettingsViewModel's dependence on MxPushRule, so that the view model could be moved into RiotSwiftUI.
- Add LocaleProvider to abstract VectorL10n's use of Matrix SDK language so it can be used in RiotSwiftUI.
- Split Theme into UKit/SwiftUI version to remove RiotSwiftUI's dependence on ThemeService and ThemeV1.
- Migrated from ThemeObserver to ThemePublisher. We push updates to ThemePublisher so that we can remove ThemeService as dependency.
- Add .DS_Store to .gitignore

Riot/Modules/Room/NotificationSettings/UIKit/RoomNotificationSettingsViewController.swift

@@ -144,7 +144,7 @@ final class RoomNotificationSettingsViewController: UIViewController {
             activityPresenter.removeCurrentActivityIndicator(animated: true)
         }
         self.viewState = viewState
-        if case let .uiKit(avatarData) = viewState.avatarData {
+        if let avatarData = viewState.avatarData as? AvatarViewDataProtocol {
             mainTableView.tableHeaderView = avatarView
             avatarView.configure(viewData: avatarData)
             avatarView.update(theme: theme)