chore: split nixos and opentofu

nixos/modules/virtualisation/containers/default.nix

@@ -0,0 +1,23 @@
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.homelab.virtualisation.containers;
+in {
+  options.homelab.virtualisation.containers.enable = lib.mkEnableOption "OCI containers";
+
+  config = lib.mkIf cfg.enable {
+    environment.systemPackages = with pkgs; [
+      nfs-utils
+    ];
+
+    virtualisation = {
+      docker = {
+        enable = true;
+        enableOnBoot = true;
+        autoPrune.enable = true;
+      };
+
+      oci-containers.backend = "docker";
+    };
+  };
+}