Doc: Rearrange files in the doc folder

Source and configuration files for each manual are now located in a
separate subdirectory, with common configuration files in doc/config.

doc
|_config
|_qtcreator
|_qtcreatordev
|_qtdesignstudio

Edit the config files accordingly.

Change-Id: Idc747a7c16e84f3e06add91234dc5fc908e64cc5
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

doc/qtcreator/examples/progressbar/main.cpp

@@ -0,0 +1,19 @@
+#include <QGuiApplication>
+#include <QQmlApplicationEngine>
+#include <QQuickView>
+
+int main(int argc, char *argv[])
+{
+    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
+
+    QGuiApplication app(argc, argv);
+
+    QQuickView view;
+    view.engine->addImportPath("qrc:/qml/imports");
+    view.setSource(QUrl("qrc:/qml/ProgressBar.ui.qml"));
+    if (!view.errors().isEmpty())
+        return -1;
+    view.show();
+
+    app.exec();
+}