Add NotificationSettings and Keywords UI and VM

Riot/Modules/Settings/Notifications/Model/NotificationSettingsScreen.swift

@@ -0,0 +1,42 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+
+@objc enum NotificationSettingsScreen: Int {
+    case defaultNotificaitons
+    case mentionsAndKeywords
+    case other
+}
+
+extension NotificationSettingsScreen: CaseIterable { }
+
+extension NotificationSettingsScreen: Identifiable {
+    var id: Int { self.rawValue }
+}
+
+extension NotificationSettingsScreen {
+    var pushRules: [PushRuleId] {
+        switch self {
+        case .defaultNotificaitons:
+            return [.oneToOneRoom, .allOtherMessages, .oneToOneEncryptedRoom, .encrypted]
+        case .mentionsAndKeywords:
+            return [.containDisplayName, .containUserName, .roomNotif, .keywords]
+        case .other:
+            return [.inviteMe, .call, .suppressBots, .tombstone]
+        }
+    }
+}