Reduce number of channels used

This was a fix attempt before I discovered that the issue was that
nixos-install uses the root user's channels. Doesn't hurt anyways.

add_channels.sh

@@ -3,7 +3,6 @@
 # TODO Surely there's more elegant?
 
 nix-channel --add https://nixos.org/channels/nixos-23.05 nixpkgs
+# Below probably only needed on non-NixOS
 nix-channel --add https://github.com/nix-community/home-manager/archive/release-23.05.tar.gz home-manager
-# First commit before 23.05 release date:
-nix-channel --add https://github.com/NixOS/nixos-hardware/archive/468a7a108108908c7a35d6549f1e1f0236a9448a.tar.gz nixos-hardware
 nix-channel --update

curacao.nix

@@ -1,7 +1,7 @@
 { ... }:
 {
   imports = [
-    <nixos-hardware/dell/g3/3779>
+    "${builtins.fetchTarball "https://github.com/NixOS/nixos-hardware/archive/468a7a108108908c7a35d6549f1e1f0236a9448a.tar.gz"}/dell/g3/3779"
     ./os/loader.nix
   ];
 

os/geoffrey.nix

@@ -1,7 +1,7 @@
 { pkgs, config, ... }:
 {
   imports = [
-    <home-manager/nixos>
+    "${builtins.fetchTarball "https://github.com/nix-community/home-manager/archive/release-23.05.tar.gz"}/nixos"
   ];
 
   users.users.geoffrey = {

os/loader.nix

@@ -7,5 +7,6 @@
     ./common.nix
     ./desktop.nix
     ./wireless.nix
+    "${builtins.fetchTarball "https://github.com/nix-community/disko/archive/3cb78c93e6a02f494aaf6aeb37481c27a2e2ee22.tar.gz"}/module.nix"
   ];
 }

pindakaas.nix

@@ -1,7 +1,8 @@
 { pkgs, config, ... }:
 {
   imports = [
-    <nixos-hardware/pine64/pinebook-pro>
+    # First commit before 23.05 release date:
+    "${builtins.fetchTarball "https://github.com/NixOS/nixos-hardware/archive/468a7a108108908c7a35d6549f1e1f0236a9448a.tar.gz"}/pine64/pinebook-pro"
     ./os/loader.nix
   ];
   # nixos-hardware use latest kernel by default. This obviously runs quickly out of sync with zfs packages.