refactor: move system specific modules into system/modules

modules/networking.nix

@@ -1,39 +0,0 @@
-#
-# Common networking settings for all machines.
-# Anything system-specific should not be here.
-#
-{
-  networking = {
-    # Enable networkManager
-    # TODO: Look into the networkManager options.
-    networkmanager.enable = true;
-
-    # Configures a simple stateful firewall.
-    # By default, it doesn't allow any incoming connections.
-    firewall = {
-      enable = true; 
-      allowedTCPPorts = [ 
-        22 # SSH
-      ];
-      allowedUDPPorts = [];
-    };
-  };
-
-  # Add binary caches to avoid having to compile them
-  nix.settings = {
-    substituters = [
-      "https://hyprland.cachix.org" 
-      "https://cuda-maintainers.cachix.org" 
-      "https://nix-community.cachix.org" 
-    ];
-    trusted-public-keys = [
-      "hyprland.cachix.org-1:a7pgxzMz7+chwVL3/pzj6jIBMioiJM7ypFP8PwtkuGc=" 
-      "cuda-maintainers.cachix.org-1:0dq3bujKpuEPMCX6U4WylrUDZ9JyUG0VpVZa7CNfq5E="
-      "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
-    ];
-  };
-
-  # TODO: look into openssh and tailscale settings.
-  services.openssh.enable = true;
-  services.tailscale.enable = true;
-}