treewide: remove impure nixpkgs

conf

@@ -4,8 +4,7 @@ if ! [ -e secrets.nix ]
 then
   git crypt unlock
 fi
-# TODO: remove nixpkgs dependency
-export NIX_PATH=yori-nix=$PWD:nixpkgs=channel:nixos-unstable
+export NIX_PATH=yori-nix=$PWD
 host=$1
 TARGET_HOST=$(nix eval --raw -f vpn.nix ips.$host)
 #TARGET_HOST=192.168.178.1

physical/3950x-hardware-config.nix

@@ -1,11 +1,11 @@
 # Do not modify this file!  It was generated by ‘nixos-generate-config’
 # and may be overwritten by future invocations.  Please make changes
 # to /etc/nixos/configuration.nix instead.
-{ config, lib, pkgs, ... }:
+{ config, lib, pkgs, modulesPath, ... }:
 
 {
   imports =
-    [ <nixpkgs/nixos/modules/installer/scan/not-detected.nix>
+    [ (modulesPath + "/installer/scan/not-detected.nix")
     ];
 
   boot.initrd.availableKernelModules = [ "nvme" "xhci_pci" "ahci" "usbhid" "usb_storage" "sd_mod" ];

physical/hetznercloud.nix

@@ -1,11 +1,10 @@
-{ config, lib, pkgs, ... }:
+{ config, lib, pkgs, modulesPath, ... }:
 let
   ipconf = (import ../secrets.nix).ipconf.${config.networking.hostName};
 in
 {
   imports =
-    # todo: impure:
-    [ <nixpkgs/nixos/modules/profiles/qemu-guest.nix>
+    [ (modulesPath + "/profiles/qemu-guest.nix")
     ];
 
   boot.kernelPackages = pkgs.linuxPackages_latest;

physical/nuc.nix

@@ -1,10 +1,10 @@
-{ config, lib, pkgs, ... }:
+{ config, lib, pkgs, modulesPath, ... }:
 let sources = import ../nix/sources.nix; 
 in
 {
 
   imports =
-    [ <nixpkgs/nixos/modules/installer/scan/not-detected.nix>
+    [ (modulesPath + "/installer/scan/not-detected.nix")
       ./.
     "${sources.nixos-hardware}/common/cpu/intel"
     ];