Add a minimal base role to record what is needed for a minimal useful system.

nix/configuration/roles/minimal_base/default.nix

@@ -0,0 +1,31 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+{
+  imports = [ ];
+
+  options.me = {
+    minimal_base.enable = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      example = true;
+      description = "Whether we want to install minimal_base.";
+    };
+  };
+
+  config = lib.mkIf config.me.minimal_base.enable {
+    me.doas.enable = true;
+    me.network.enable = true;
+    me.nvme.enable = true;
+    me.ssh.enable = true;
+    me.sshd.enable = true;
+    me.user.enable = true;
+    me.zfs.enable = true;
+    me.zrepl.enable = true;
+    me.zsh.enable = true;
+  };
+}