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.
This is achieved by generating the Home Manager configuration
file as `~/.config/task/home-manager-taskrc`, and including that
file into ~/.config/task/taskrc.
Fixes#2360
Co-authored-by: mainrs <5113257+mainrs@users.noreply.github.com>
Co-authored-by: Nicolas Berbiche <nicolas@normie.dev>
