QDS-11236 Integrate with demo project endpoint

This MR brings the following features;

• Get the demo list from provided rest api
• Check the last update time of the local cache via rest api

src/backend.cpp

@@ -240,17 +240,29 @@ void Backend::runDemoProject(const QString &projectName)
     qDebug() << "Checking if demo project is cached for " << projectName;
     emit popupOpen();
 
-    const bool cached = m_projectManager->isDemoProjectCached(projectName);
+    // sample project info
+    // [{"lastUpdate":1701947766739.9812,"name":"ClusterTutorial.qmlrc"}]
+    const QJsonArray projectList = m_serviceConnector->fetchUserDemoList();
+    QJsonObject projectInfo;
+    for (auto project : projectList) {
+        if (projectName == project.toObject().value("name").toString().remove(".qmlrc")) {
+            projectInfo = project.toObject();
+            break;
+        }
+    }
+
+    const bool cached = m_projectManager->isDemoProjectCached(projectInfo);
 
     if (!cached) {
         updatePopup("Downloading demo project...", false);
 
-        const QString url = "https://designviewer.qt.io/qmlprojects/" + projectName + ".qmlrc";
+        const QString url = "https://designviewer.qt.io/qmlprojects/demos/" + projectName
+                            + ".qmlrc";
         QByteArray project = m_serviceConnector->fetchProject(url);
         qDebug() << "Demo project is not cached. Trying to download from " << url << " ...";
 
         updatePopup("Caching demo project...");
-        if (!m_projectManager->cacheDemoProject(project, projectName)) {
+        if (!m_projectManager->cacheDemoProject(project, projectInfo)) {
             qCritical()
                 << "Could not cache demo project. Please check the logs for more information.";
             emit popupClose();