Update "Converting UI Projects to Applications"

About https://doc.qt.io/qtdesignstudio/quick-converting-ui-projects.html
 
For users who are not yet familiar with Qt, link to: https://doc.qt.io/qt-5/qtqml-cppintegration-overview.html
 
We also have to add something about qt-labs/qtquickdesigner-components, which contains all the custom QDS specific modules.
 
Adding Qt Quick Design Studio Modules to Qt Installations
 
To add the Qt Design Studio specific Components to your Qt you have to checkout and install the module.
 
git clone "ssh://user@codereview.qt-project.org:29418/qt-labs/qtquickdesigner-components"
 
Then use qmake from your Qt installation to build the module and to add it to your Qt. Switch to the directory that contains the sources (usually, qtquickdesigner-components), and enter the following commands:
 
<path_to_qmake>\qmake -r
make
make install
 
On Windows, use the nmake and nmake install commands instead.