Don't start the entire NeoChat backend when receiving push notifications

This adds a dedicated "set up for push notifications only" function in
Controller, which only sets up the KUnifiedPush connector for receiving
the message and then quitting right afterward. If the user tries to
open a notification, then it will quit and open the main client.

src/notificationsmanager.cpp

@@ -16,6 +16,10 @@
 #include <Quotient/csapi/pushrules.h>
 #include <Quotient/user.h>
 
+#ifdef HAVE_KIO
+#include <KIO/ApplicationLauncherJob>
+#endif
+
 #include "controller.h"
 #include "neochatconfig.h"
 #include "neochatconnection.h"
@@ -319,10 +323,15 @@ void NotificationsManager::postPushNotification(const QByteArray &message)
             notification->setText(i18n("Encrypted Message"));
         }
 
+#ifdef HAVE_KIO
         auto openAction = notification->addAction(i18n("Open NeoChat"));
         connect(openAction, &KNotificationAction::activated, this, [=]() {
-            WindowController::instance().showAndRaiseWindow(notification->xdgActivationToken());
+            auto *job = new KIO::ApplicationLauncherJob(KService::serviceByDesktopName(QStringLiteral("org.kde.neochat")));
+            job->start();
         });
+#endif
+
+        connect(notification, &KNotification::closed, qGuiApp, &QGuiApplication::quit);
 
         notification->sendEvent();