Add compatibility for non-FHS 3.0 systems

* Added `shell.nix` definition for temporary development environment for Nix(OS)
* Set uuidgen and other binaries check to not rely on hard-codded paths

shell.nix

@@ -0,0 +1,8 @@
+# Configuration file for Nix(OS) to provide a temporary development enviroment
+
+{ pkgs ? import <nixpkgs> {} }:
+  pkgs.mkShell {
+    nativeBuildInputs = with pkgs.buildPackages; [
+      util-linux # Needed for uuidgen
+    ];
+}