Add default settings stored in the .ini file

[PawelekPro]

To do:

• Development of a class to handle global application settings
• Handling the .ini file, which in a Unix environment is stored in /home/user/.config/app, and in a Windows environment C:\Users\User\AppData\Roaming\App
• Development of global app settings in terms of UX

[PawelekPro]

To be implemented: https://github.com/githubuser0xFFFF/Qt-Advanced-Stylesheets?tab=readme-ov-file (It's necessary to adapt this code for CMake)