Remove challenge response auth, authorize spike to build

sets/builder.nix

@@ -9,6 +9,7 @@
     useDefaultShell = true;
     openssh.authorizedKeys.keys = [
       "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIFOBdARV3DVx4fKTf1hCSmOz+S06pI28cvrdo+FbWDP/ root@rainbowdash"
+      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIElCYORRBERl/as01Obp1Og/mdy28V7gw32uCZseOSZt root@spike"
     ];
   };
 }

sets/ssh.nix

@@ -4,6 +4,7 @@
   services.openssh = {
     enable = true;
     passwordAuthentication = false;
+    challengeResponseAuthentication = false;
   };
   # users.users.artemis.openssh.authorizedKeys.keys set in private
 }

system/spike/default.nix

@@ -9,6 +9,7 @@
     ../../sets/hacking.nix
     ../../sets/laptop.nix
     ../../sets/ssh.nix
+    ../../sets/buildMachines.nix
     ../../sets/workstation.nix
   ];