refactor hydra jobs

Signed-off-by: ahuston-0 <aliceghuston@gmail.com>

.hydra/jobs.nix

@@ -0,0 +1,10 @@
+{ inputs, outputs }:
+let
+  inherit (inputs.nixpkgs.lib) mapAttrs;
+
+  getCfg = _: cfg: cfg.config.system.build.toplevel;
+in
+{
+  hosts = mapAttrs getCfg outputs.nixosConfigurations;
+  formatter = outputs.formatter;
+}