Add FTUE display name screen.

Use UserSession instead of userId & MXSession in OnboardingCoordinator

RiotSwiftUI/Modules/Onboarding/DisplayName/Service/MatrixSDK/OnboardingDisplayNameService.swift

@@ -0,0 +1,52 @@
+// 
+// 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
+import Combine
+
+@available(iOS 14.0, *)
+class OnboardingDisplayNameService: OnboardingDisplayNameServiceProtocol {
+    
+    enum ServiceError: Error {
+        case unknown
+    }
+    
+    // MARK: - Properties
+    
+    // MARK: Private
+    
+    private let userSession: UserSession
+    
+    // MARK: Public
+    
+    var displayName: String? {
+        userSession.account.userDisplayName
+    }
+    
+    // MARK: - Setup
+    
+    init(userSession: UserSession) {
+        self.userSession = userSession
+    }
+    
+    func setDisplayName(_ displayName: String, completion: @escaping (Result<Bool, Error>) -> Void) {
+        userSession.account.setUserDisplayName(displayName) {
+            completion(.success(true))
+        } failure: { error in
+            completion(.failure(error ?? ServiceError.unknown))
+        }
+    }
+}