Add configuration for Pi Nix images

pi-imgs/pi-initial.nix

@@ -0,0 +1,27 @@
+{ lib, pkgs, ... }: {
+  imports = [
+    <nixpkgs/nixos/modules/installer/sd-card/sd-image-aarch64-installer.nix>
+  ];
+
+  users.users.root.openssh.authorizedKeys.keys = [
+     "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILIztwQxt+jqroFONSgq+xzPMuE2I5Dq/zWPQ8RcTYJr gabriel@gitgalaxy.com"
+  ];
+  # bzip2 compression takes loads of time with emulation, skip it.
+  sdImage.compressImage = false;
+  # OpenSSH is forced to have an empty `wantedBy` on the installer system[1], this won't allow it
+  # to be started. Override it with the normal value.
+  # [1] https://github.com/NixOS/nixpkgs/blob/9e5aa25/nixos/modules/profiles/installation-device.nix#L76
+  systemd.services.openssh.wantedBy = lib.mkOverride 40 [ "multi-user.target" ];
+  # Enable OpenSSH out of the box.
+  services.openssh.enable = true;
+  
+  environment.systemPackages = with pkgs; [
+    vim
+    wget
+    htop
+    git
+    screen
+    nix-output-monitor
+    tailscale
+  ];
+}