hippocampus: Allow hydra build riscv

TODO: Replace the deployment with microvms similar to how it's
implemented in https://gitea.c3d2.de/c3d2

machines/hippocampus/riscv.nix

@@ -1,4 +1,4 @@
-{ config, pkgs, lib, ... ]: {
+{ config, pkgs, lib, ... }: {
   boot.binfmt.emulatedSystems = [
     "riscv64-linux"
   ];

machines/hippocampus/servers/public/hydra.nix

@@ -1,14 +1,4 @@
 {config, pkgs, ...}: let
-  deploy-container = pkgs.writeScriptBin "deploy-nixos-container" ''
-    pushd $2
-    nixos-container update $1 --flake $2#$3
-    git reset --hard HEAD
-    git clean -fdx
-    git reflog expire --expire=now --all
-    git repack -ad  # Remove dangling objects from packfiles
-    git prune       # Remove dangling loose objects
-    popd
-  '';
 in {
   imports = [
     # ./nix-serve.nix
@@ -42,42 +32,13 @@ in {
       
     ];
   };
-  # Deployment User
-  users.users.hydra-deploy = {
-    isNormalUser = true;
-    home = "/var/lib/hydra/deploy";
-    description = "Hydra Deployment User";
-    extraGroups = [ "hydra" ];
-    packages = [
-      deploy-container
-    ];
-  };
-  # TODO: Configure authorizedKeys between
-  # hydra-queue-runner and hydra-deploy
-  security.sudo.extraRules = [
-    {
-      users = ["hydra-deploy"];
-      commands = [
-        {
-          command = "${deploy-container}/bin/deploy-nixos-container *";
-          options = ["NOPASSWD"];
-        }
-      ];
-    }
-  ];
-  networking.nat = {
-    enable = true;
-    internalInterfaces = [
-      "ve-newalan"
-      "ve-handyhelper"
-    ];
-    externalInterface = "enp0s25";
-    enableIPv6 = true;
-  };
-
+  
   nix.buildMachines = [
     { hostName = "localhost";
-      system = "x86_64-linux";
+      systems = [
+        "x86_64-linux"
+        "riscv64-linux"
+      ];
       supportedFeatures = ["kvm" "nixos-test" "big-parallel" "benchmark"];
       maxJobs = 8;
     }