My specifications:
- Nix code should receive a permissive license, in part not to copyleft
away everyone's NixOS configurations for no good reason.
- The companion tool should be protected by copyleft.
- The templates should immediately rise to the public domain.
- It should be very clear which part falls under which license.
Based on that, I have selected the ISC and BSD-0 because they are short,
and the GNU General Public License version 3 or later as a copyleft
license.
