Motivation for this change

Looking to add some QT/KDE themes to NixOS so I can make my desktop pretty. Thought I would share. This seems to work out of the box.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• [x Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.