Stubbing not working with the default cfg.finalPackage. Pass null to reduce closure size
Instead of having to manually stub packages that should not be downloaded we instead automatically stub all packages (except a small list of whitelisted ones). Tests can re-introduce the real package by using the `realPkgs` module argument.
* ranger: stub tests * alacritty: stub tests * broot: stub tests * zsh: stub tests * vim-vint: stub tests