Room screen header (#86)

* #35 Create `ElementNavigationController` subclass

* #35 Add encryption icons

* #35 Add avatar and encryption badge image to the room screen view model

* #35 Create `RoomHeaderView` class

* #35 Replace room title with a RoomHeaderView instance in the toolbar

* #35 Add changelog

* #35 Introduce `UITestScreenIdentifier` and refactor ui tests

* #35 Fix old tests

* #35 add some tests for room screen

* #35 Use svgs instead of pngs

* #35 Fix PR remarks

ElementX/Sources/UITestsRootView.swift

@@ -11,14 +11,15 @@ import SwiftUI
 struct UITestsRootView: View {
     
     let mockScreens: [MockScreen]
-    var selectionCallback: ((String) -> Void)?
+    var selectionCallback: ((UITestScreenIdentifier) -> Void)?
     
     var body: some View {
         NavigationView {
             List(mockScreens) { coordinator in
-                Button(coordinator.id) {
+                Button(coordinator.id.description) {
                     selectionCallback?(coordinator.id)
                 }
+                .accessibilityIdentifier(coordinator.id.rawValue)
             }
             .listStyle(.plain)
         }