add files for create room screen, add selected users section with test

ElementX/Sources/Screens/CreateRoom/CreateRoomViewModel.swift

@@ -0,0 +1,43 @@
+//
+// 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 Combine
+import SwiftUI
+
+typealias CreateRoomViewModelType = StateStoreViewModel<CreateRoomViewState, CreateRoomViewAction>
+
+class CreateRoomViewModel: CreateRoomViewModelType, CreateRoomViewModelProtocol {
+    private var actionsSubject: PassthroughSubject<CreateRoomViewModelAction, Never> = .init()
+    
+    var actions: AnyPublisher<CreateRoomViewModelAction, Never> {
+        actionsSubject.eraseToAnyPublisher()
+    }
+
+    init(selectedUsers: [UserProfile]) {
+        super.init(initialViewState: CreateRoomViewState(selectedUsers: selectedUsers))
+    }
+    
+    // MARK: - Public
+    
+    override func process(viewAction: CreateRoomViewAction) {
+        switch viewAction {
+        case .createRoom:
+            actionsSubject.send(.createRoom)
+        case .deselectUser(let user):
+            state.selectedUsers.removeAll(where: { $0.userID == user.userID })
+        }
+    }
+}