knot-resolver: add luaPackages.psl

      # For http module, prefill module, trust anchor bootstrap.

      # It brings lots of deps; some are useful elsewhere (e.g. cqueues).

      http

      # psl isn't in nixpkgs yet, but policy.slice_randomize_psl() seems not important.

      # used by policy.slice_randomize_psl()

      psl

    ];

    preferLocalBuild = true;

    allowSubstitutes = false;