Implement final cmakfiles.txt generation based on AuroraCluster example

Use AuroraCluster example as template for cmakfiles.txt generation

See: https://git.qt.io/public-demos/qtdesign-studio/-/tree/master/playground/AuroraCluster

All generated files that are supposed to be regenerated now contain a comment.
main.cpp and the main cmakefiles.tst do not contain this commen, since we expect users to change those.

The parts from main.cpp and the main cmakefiles.txt that are expected to change again are
included from external files (qmlmodules and import_qml_plugins.h)

qmlmodules contains the QML specfic parts and links each module. If modules are added this file would change. The same applies to import_qml_plugins.h. The header file ensures that the linked does not discard the modules, since for each module now a symbol is directly referenced.

The files main.cpp and import_qml_plugins.h were moved to a "src" folder and the main QML module is always called 'content'.

To avoid name clashes the main applicatin target is called ProjectNameApp, so it does not clash with the module of the same name.

Each cmakefiles.txt for QML contains a statement like this: qt_add_library(Data STATIC)
This statement ensures that the module is statically linked which makes deployment easier, but requires_ import_qml_plugins.h_ and the explicit linkage in qmlmodules.