steveej-x13s-rmvbl: init with minimal setup

this configures a standalone USB device that doesn't need configuration
of the firmware's EFI variables.

nix/devShells.nix

@@ -1,27 +1,27 @@
-{
-  inputs',
-  packages',
-  pkgs,
+{ inputs'
+, packages'
+, pkgs
+,
 }:
 pkgs.stdenv.mkDerivation {
   name = "infra-env";
   buildInputs =
     [
-      (with pkgs.callPackage (pkgs.path + "/nixos") {configuration = {};};
-        with config.system.build; [
-          nixos-generate-config
-          nixos-install
-          nixos-enter
-          manual.manpages
-        ])
+      (with pkgs.callPackage (pkgs.path + "/nixos") { configuration = { }; };
+      with config.system.build; [
+        nixos-generate-config
+        nixos-install
+        nixos-enter
+        manual.manpages
+      ])
     ]
     ++ (with pkgs; [
       inputs'.colmena.packages.colmena
       nixos-install-tools
       dconf2nix
       inputs'.nixos-anywhere.packages.nixos-anywhere
+      inputs'.disko.packages.default
       nurl
-
       just
       git-crypt
       vcsh