Add network manager firewalld, enable gobject introspection

This pull request brings some quite big changes to make firewalld work:

- Python packages using gtk3 require **gobject introspection** to work. It was not enabled before, so i had to enable it in **gdk_pixbuf, gtk3, atk, pango, pygobject3, libnotify and network-manager** to make firewalld work.
It should not cause any problems, because apps(mostly native) not using introspection just don't care.
- The way i export gobject introspection typelib path is by using passthru.
- One exeception which could cause problems is libnotify. Now it depend on gtk3, because i was not able to make it work otherwise. I don't know if this is bad or not.

I would also need some help implementing nixos firewalld module. I think this package can help many. Thanks!