refactor nix settings

nix/os/devices/sj-bm-hostkey0/configuration.nix

@@ -19,6 +19,7 @@
     repoFlake.inputs.sops-nix.nixosModules.sops
 
     ../../profiles/common/user.nix
+    ../../snippets/nix-settings-holo-chain.nix
 
     # TODO
     # ./network.nix
@@ -47,19 +48,6 @@
   services.openssh.enable = true;
   services.openssh.settings.PermitRootLogin = "yes";
 
-  nix.nixPath = [
-    "nixpkgs=${pkgs.path}"
-  ];
-
-  nix.registry = {
-    nixpkgs.to = {
-      type = "path";
-      path = pkgs.path;
-    };
-  };
-
-  nix.settings.experimental-features = ["nix-command" "flakes" "ca-derivations"];
-
   boot = {
     kernel = {
       sysctl = {

nix/os/devices/steveej-t14/system.nix

@@ -8,21 +8,15 @@
 }: let
   passwords = import ../../../variables/passwords.crypt.nix;
 in {
+  imports = [
+    ../../snippets/nix-settings-holo-chain.nix
+  ];
+
   nix.settings = {
     substituters = [
-      "https://holochain-ci.cachix.org"
-      "https://holochain-ci-internal.cachix.org"
-      # "https://cache.holo.host/"
     ];
     trusted-public-keys = [
-      "holochain-ci.cachix.org-1:5IUSkZc0aoRS53rfkvH9Kid40NpyjwCMCzwRTXy+QN8="
-      "holochain-ci-internal.cachix.org-1:QvVsSrTiearCjrLTVtNtJOdQCDTseXh7UXUuSMx46NE="
-      "cache.holo.host-1:lNXIXtJgS9Iuw4Cu6X0HINLu9sTfcjEntnrgwMQIMcE="
-      "cache.holo.host-2:ZJCkX3AUYZ8soxTLfTb60g+F3MkWD7hkH9y8CgqwhDQ="
     ];
-
-    extra-experimental-features = ["impure-derivations"];
-    system-features = ["recursive-nix" "big-parallel"];
   };
 
   networking.extraHosts = ''