feat: Unify all of the nixos substituters

nixos/ryu/configuration.nix

@@ -12,6 +12,7 @@
     ./apps
     ./vms
     ./games
+    ../../modules/nixos/substituters.nix
   ];
 
   security.tpm2 = {
@@ -46,18 +47,6 @@
       auto-optimise-store = true;
       extra-experimental-features = "nix-command flakes auto-allocate-uids";
       trusted-users = [device.user];
-      trusted-substituters = [
-        "https://nix-community.cachix.org"
-        "https://nixos-raspberrypi.cachix.org"
-        "https://llama-cpp.cachix.org"
-        "https://cuda-maintainers.cachix.org"
-      ];
-      trusted-public-keys = [
-        "cuda-maintainers.cachix.org-1:0dq3bujKpuEPMCX6U4WylrUDZ9JyUG0VpVZa7CNfq5E="
-        "llama-cpp.cachix.org-1:H75X+w83wUKTIPSO1KWy9ADUrzThyGs8P5tmAbkWhQc="
-        "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
-        "nixos-raspberrypi.cachix.org-1:4iMO9LXa8BqhU+Rpg6LQKiGa2lsNh/j2oiYLNOQ5sPI="
-      ];
     };
     extraOptions = ''
       build-users-group = nixbld
@@ -76,6 +65,11 @@
       # ../../builders/tsuba.nix
     ];
     distributedBuilds = true;
+    # Enable CUDA and llama-cpp caches
+    substituters = {
+      enableCuda = true;
+      enableLlamaCpp = true;
+    };
   };
 
   users.users.${device.user} = {