Disable password expiry

Since we set RTC in the Nix build it's likely that any passwords have
expired since the image generation RTC time.

Ideally this should be applied in autounattend.xml but it didn't work
out either as FirstLogonCommands or as a command in the specialize pass.

wfvm/win.nix

@@ -156,7 +156,17 @@ let
     echo "Done"
 
     mv c.img $out
-  '')) baseImage installCommands;
+  '')) baseImage (
+    [
+      {
+        name = "DisablePasswordExpiry";
+        script = ''
+          win exec 'wmic UserAccount set PasswordExpires=False'
+        '';
+      }
+    ] ++
+    installCommands
+  );
 
 in