Enable e2ee support (#274)

* Enable sliding sync common extensions and session verification banner display; fix user session flow coordinator state machine
* Fixed a couple of deprecation warnings
* Add missing `m.room.encryption` required state
* Switch to rust-sdk v1.0.15-alpha and add changelog

ElementX/Sources/UserSession/UserSessionFlowCoordinator.swift

@@ -112,7 +112,7 @@ class UserSessionFlowCoordinator: Coordinator {
             case .presentRoom(let roomIdentifier):
                 self.stateMachine.processEvent(.showRoomScreen(roomId: roomIdentifier))
             case .presentSettings:
-                self.presentSettingsScreen()
+                self.stateMachine.processEvent(.showSettingsScreen)
             case .presentBugReport:
                 self.presentBugReportScreen()
             case .verifySession:
@@ -209,6 +209,8 @@ class UserSessionFlowCoordinator: Coordinator {
 
         navigationRouter.dismissModule()
         remove(childCoordinator: coordinator)
+        
+        stateMachine.processEvent(.dismissedSettingsScreen)
     }
     
     // MARK: Session verification

ElementX/Sources/UserSession/UserSessionFlowCoordinatorStateMachine.swift

@@ -89,6 +89,14 @@ class UserSessionFlowCoordinatorStateMachine {
                 return .suspended
             case (.becomeActive, .suspended):
                 return self.stateBeforeSuspension
+            case (.showSettingsScreen, .homeScreen):
+                return .settingsScreen
+            case (.dismissedSettingsScreen, .settingsScreen):
+                return .homeScreen
+            case (.showSessionVerificationScreen, .homeScreen):
+                return .sessionVerificationScreen
+            case (.dismissedSessionVerificationScreen, .sessionVerificationScreen):
+                return .homeScreen
             default:
                 return nil
             }