Refactor DeviceVerification prefix classes to KeyVerification where needed. And move key verification related classes into the same module KeyVerification.

Riot/Modules/KeyVerification/Device/Start/DeviceVerificationStartViewState.swift

@@ -0,0 +1,29 @@
+// File created from ScreenTemplate
+// $ createScreen.sh DeviceVerification/Start DeviceVerificationStart
+/*
+ Copyright 2019 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
+
+/// DeviceVerificationStartViewController view state
+enum DeviceVerificationStartViewState {
+    case loading
+    case loaded     // started
+    case verifyUsingLegacy(MXSession, MXDeviceInfo)
+    case cancelled(MXTransactionCancelCode)
+    case cancelledByMe(MXTransactionCancelCode)
+    case error(Error)
+}