now using flake-parts; refactored nixosConfigurations; using hm standalone

hosts/modules/common/nix.nix

@@ -0,0 +1,40 @@
+{ inputs, ... }:
+
+{
+  imports = [ inputs.nixos-cli.nixosModules.nixos-cli ];
+
+  nix = {
+    settings = {
+      auto-optimise-store = true;
+      connect-timeout = 10;
+      log-lines = 25;
+      min-free = 128000000;
+      max-free = 1000000000;
+      trusted-users = [ "@wheel" ];
+    };
+    extraOptions = "experimental-features = nix-command flakes";
+    gc = {
+      automatic = true;
+      options = "--delete-older-than 8d";
+    };
+  };
+
+  nixpkgs.config = {
+    allowUnfree = true;
+    enableParallelBuilding = true;
+    buildManPages = false;
+    buildDocs = false;
+  };
+
+  services = {
+    nixos-cli = {
+      enable = true;
+      config = {
+        use_nvd = true;
+        ignore_dirty_tree = true;
+      };
+    };
+  };
+
+  system.stateVersion = "22.11";
+}