No more `{allowed,trusted}-users`: Getting the Nix daemon out of the business of authentication

Hi, I would like to kick off a discussion about an idea that I had that keeps on coming up in Nix discussions. I want to involve the wider community because the gist of the idea is moving responsibility from Nix to the OS, so I want to make sure that NixOS maintainers are on board with this. Essentially the idea is that instead of Nix doing authentication, the OS should do it. In particular, there should be separate trusted and untrusted socket files. Nix will then “blindly” accept incoming con...