* removed QtSourceGroupWizard, QtSourceGroupWizardPage and context types
* removed isInForm flag of QtProjectWizardContent
* added check of empty source paths
* set project window as parent for message boxes, so they don't get hidden behind main window
* fixed issues when removing and duplicating source groups
* updated project setup tests to no steps
* removed preprocessor guards in language specific files to avoid "file has no symbols" warning
* separated files into multiple lists in lib and lib_gui CMakeLists.txt for each language package
* in addition: add unloadable sourcegroup to visualize, load and save information when loading a project that contains source groups that are not supported by the build