Add cudainfo program to test CUDA in sandbox

The cudainfo program is executed inside the build sandbox so we can see
if it works properly. It uses the autoAddDriverRunpath hook to inject in
the runpath the location of the library directory for CUDA libraries.

m/module/nvidia.nix

@@ -1,4 +1,4 @@
-{ lib, config, ... }:
+{ lib, config, pkgs, ... }:
 {
   # Configure Nvidia driver to use with CUDA
   hardware.nvidia.package = config.boot.kernelPackages.nvidiaPackages.production;
@@ -15,4 +15,6 @@
   programs.nix-required-mounts.allowedPatterns.nvidia-gpu.paths = [
     config.systemd.tmpfiles.settings.graphics-driver."/run/opengl-driver"."L+".argument
   ];
+
+  environment.systemPackages = [ pkgs.cudainfo ];
 }