Support dark mode on Windows

Default windowsvista style used on Windows does not support a dark mode (which is present in modern Windows 10 and Windows 11).

To solve this issue, we can switch used style from windowsvista to windows (which supports the dark mode) and apply a qss stylesheet to make target application to look as with windowsvista style, just with different colors. Something like this:

Note that Qt 6.7 introduces a new windows11 style with dark mode support (used by default on Windows 11), but it does not work on Windows 10.