kanidm: require big-parallel for building

Build has timed out and been killed multiple times on hydra builds. This forces users to attempt to build it themselves, which they cannot due without sufficient resources.

pkgs/by-name/ka/kanidm/package.nix

@@ -122,6 +122,9 @@ rustPlatform.buildRustPackage rec {
     withSecretProvisioning = kanidm.override { enableSecretProvisioning = true; };
   };
 
+  # can take over 4 hours on 2 cores and needs 16GB+ RAM
+  requiredSystemFeatures = [ "big-parallel" ];
+
   meta = with lib; {
     changelog = "https://github.com/kanidm/kanidm/releases/tag/v${version}";
     description = "Simple, secure and fast identity management platform";