QmlDesigner: Move CMake generator to QmlProjectManager

Task-number: QDS-6898
Change-Id: Ib1ca2ff4cd17a1ee6c203878a963bf44bac6969b
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmlprojectmanager/cmakegen/qmlprojectmaincpp.tpl

@@ -0,0 +1,61 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Quick Studio Components.
+**
+** $QT_BEGIN_LICENSE:GPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 or (at your option) any later version
+** approved by the KDE Free Qt Foundation. The licenses are as published by
+** the Free Software Foundation and appearing in the file LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QGuiApplication>
+#include <QQmlApplicationEngine>
+
+#include "app_environment.h"
+#include "import_qml_plugins.h"
+
+int main(int argc, char *argv[])
+{
+    set_qt_environment();
+    QGuiApplication app(argc, argv);
+
+    QQmlApplicationEngine engine;
+    const QUrl url(u"qrc:Main/main.qml"_qs);
+    QObject::connect(
+                &engine, &QQmlApplicationEngine::objectCreated, &app,
+                [url](QObject *obj, const QUrl &objUrl) {
+        if (!obj && url == objUrl)
+            QCoreApplication::exit(-1);
+    },
+    Qt::QueuedConnection);
+
+    engine.addImportPath(QCoreApplication::applicationDirPath() + "/qml");
+    engine.addImportPath(":/");
+
+    engine.load(url);
+
+    if (engine.rootObjects().isEmpty()) {
+        return -1;
+    }
+
+    return app.exec();
+}