Clean up aspi and kardorf configs

hosts/common/optional/avahi.nix

@@ -0,0 +1,9 @@
+{
+  # MDNS on local network
+  services.avahi = {
+    enable = true;
+    nssmdns4 = true;
+    publish.enable = true;
+    publish.addresses = true;
+  };
+}