add System general controls class to configure common system configurations

[Dozingfiretruck]

add System general controls class to configure common system configurations
such as
System general controls:
--icon=ICON_PATH

the icon in different systems have different commands，ues it to unification

[kayhayen]

I will welcome the PR that achieves this. Icon inputs are different for all platforms. Nuitka allows you to convert them on the fly, but it's never going to be the only option, or else people who care will miss out on OS-specific features.

I think it would be nice if somebody started by demonstrating a workflow that produces optimal icons for all platforms, then maybe we can optimize for that.