Epic: create and join rooms - Start Chat (#680)

* add start chat flow with UI

* add feature flag for start chat

* add changelog

* fix naming and tests

* fix empty display name in user cell

* Update ElementX/Sources/Application/AppSettings.swift

Co-authored-by: Alfonso Grillo <alfogrillo@element.io>

* add screenshots from UI test

* fix swiftFormat and add identifiers

* fix warnings

---------

Co-authored-by: Alfonso Grillo <alfogrillo@element.io>

ElementX/Sources/Screens/HomeScreen/HomeScreenModels.swift

@@ -24,6 +24,7 @@ enum HomeScreenViewModelAction {
     case presentSettingsScreen
     case presentInviteFriendsScreen
     case presentFeedbackScreen
+    case presentStartChatScreen
     case signOut
 }
 
@@ -37,6 +38,7 @@ enum HomeScreenViewUserMenuAction {
 enum HomeScreenViewAction {
     case selectRoom(roomIdentifier: String)
     case userMenu(action: HomeScreenViewUserMenuAction)
+    case startChat
     case verifySession
     case skipSessionVerification
     case updateVisibleItemRange(range: Range<Int>, isScrolling: Bool)
@@ -67,6 +69,10 @@ struct HomeScreenViewState: BindableState {
     
     var roomListMode: HomeScreenRoomListMode = .skeletons
     
+    var showStartChatFlowEnabled: Bool {
+        ServiceLocator.shared.settings.startChatFlowFeatureFlag
+    }
+    
     var visibleRooms: [HomeScreenRoom] {
         if roomListMode == .skeletons {
             return placeholderRooms