♻️ consolidate nix configs

nix/modules/base/common.nix

@@ -0,0 +1,39 @@
+{ pkgs, ... }:
+
+{
+  environment.systemPackages = with pkgs; [
+    dogdns
+    htop
+    inetutils
+    vim
+  ];
+
+  nix = {
+    extraOptions = ''
+      experimental-features = nix-command flakes
+    '';
+
+    gc = {
+      automatic = true;
+    };
+
+    settings = {
+      substituters = [
+        "https://walkah.cachix.org"
+        "https://cache.garnix.io"
+      ];
+
+      trusted-public-keys = [
+        "walkah.cachix.org-1:D8cO78JoJC6UPV1ZMgd1V5znpk3jNUERGIeAKN15hxo="
+        "cache.garnix.io:CTFPyKSLcx5RMJKfLo5EEPUObbA78b0YQ2DTCJXqr9g="
+      ];
+    };
+  };
+
+  programs = {
+    zsh = {
+      enable = true;
+      promptInit = "";
+    };
+  };
+}