As a developer, I want to easily add Qt-related files to the project.

These file types I want to add:

• Qt-related new class (with QObject/QWidget boiler-plate)
• a .ui file
• a .qml file
• a .ts file with an option to choose the language
• maybe a new .qrc file (we recommend using qt_add_resource these
  days, so maybe not)

Get inspiration from Qt VS Tools and Qt Creator for which types we want to support exactly.

The files should be added to the file system.

Tentative: the files should be added to the CMake project file if possible.