RoomPowerLevel: Add dedicated file and convenient init.

Riot/Model/Room/RoomPowerLevel.swift

@@ -0,0 +1,44 @@
+/*
+ Copyright 2020 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
+
+/// Riot Standard Room Member Power Level
+@objc
+public enum RoomPowerLevel: Int {
+    case admin = 100
+    case moderator = 50
+    case user = 0
+    
+    public init?(rawValue: Int) {
+        switch rawValue {
+        case 100...:
+            self = .admin
+        case 50...99:
+            self = .moderator
+        default:
+            self = .user
+        }
+    }
+}
+
+@objcMembers
+public final class RoomPowerLevelHelper: NSObject {
+    
+    static func roomPowerLevel(from rawValue: Int) -> RoomPowerLevel {
+        return RoomPowerLevel(rawValue: rawValue) ?? .user
+    }
+}