Initial setup ready for PIN/Biometric app lock. (#1876)

* Add AppLockCoordinator and WindowManager.

ElementX/Sources/Services/AppLock/AppLockService.swift

@@ -0,0 +1,55 @@
+//
+// Copyright 2023 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 LocalAuthentication
+
+@MainActor
+protocol AppLockServiceProtocol {
+    /// The app has been configured to automatically lock with a PIN code.
+    var isEnabled: Bool { get }
+    /// The app can additionally be unlocked using FaceID or TouchID.
+    var supportsBiometrics: Bool { get }
+    /// The app should be unlocked with a PIN code/biometrics before being presented.
+    var needsUnlock: Bool { get }
+    
+    /// Attempt to unlock the app with the supplied PIN code.
+    func unlock(with pinCode: String) -> Bool
+    /// Attempt to unlock the app using FaceID or TouchID.
+    func unlockWithBiometrics() -> Bool
+}
+
+class AppLockService: AppLockServiceProtocol {
+    private let keychainController: KeychainControllerProtocol
+    private let appSettings: AppSettings
+    
+    var isEnabled: Bool { appSettings.appLockFlowEnabled }
+    var supportsBiometrics: Bool { true }
+    var needsUnlock: Bool { true }
+    
+    init(keychainController: KeychainControllerProtocol, appSettings: AppSettings) {
+        self.keychainController = keychainController
+        self.appSettings = appSettings
+    }
+    
+    func unlock(with pinCode: String) -> Bool {
+        true
+    }
+    
+    func unlockWithBiometrics() -> Bool {
+        guard supportsBiometrics else { return false }
+        return true
+    }
+}