Add App Lock settings screen (#1917)

ElementX/Sources/Screens/AppLock/AppLockScreen/AppLockScreenModels.swift

@@ -0,0 +1,40 @@
+//
+// Copyright 2022 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
+
+enum AppLockScreenViewModelAction {
+    /// The user has successfully unlocked the app.
+    case appUnlocked
+}
+
+struct AppLockScreenViewState: BindableState {
+    var bindings: AppLockScreenViewStateBindings
+}
+
+struct AppLockScreenViewStateBindings { }
+
+enum AppLockScreenViewAction: CustomStringConvertible {
+    /// Attempt to unlock the app with the supplied PIN code.
+    case submitPINCode(String)
+    
+    var description: String {
+        switch self {
+        case .submitPINCode:
+            return "submitPINCode"
+        }
+    }
+}