Reorganize imports

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

hosts/common/configs/system/impermanence/default.nix

@@ -0,0 +1,45 @@
+{ config, pkgs, ... }:
+{
+  imports = [ ./options.nix ];
+
+  boot.initrd.systemd = {
+    enable = true;
+
+    initrdBin = with pkgs; [
+      coreutils
+      util-linux
+      findutils
+      btrfs-progs
+    ];
+
+    services.impermanence = {
+      description = "Rollback BTRFS subvolumes to a pristine state";
+      wantedBy = [ "initrd.target" ];
+      before = [ "sysroot.mount" ];
+      after = [ "cryptsetup.target" ];
+      unitConfig.DefaultDependencies = false;
+      serviceConfig.Type = "oneshot";
+      environment.DEVICE = config.environment.impermanence.device;
+      script = builtins.readFile ./scripts/wipe.sh;
+    };
+  };
+
+  # uuidgen -r | tr -d -
+  # https://github.com/NixOS/nixpkgs/blob/master/nixos/doc/manual/administration/systemd-state.section.md
+  # https://github.com/NixOS/nixpkgs/pull/286140/files
+  # https://git.eisfunke.com/config/nixos/-/blob/e65e1dc21d06d07b454005762b177ef151f8bfb6/nixos/machine-id.nix
+  sops.secrets."machineId".mode = "0444";
+
+  environment = {
+    etc."machine-id".source = pkgs.runCommandLocal "machine-id-link" { } ''
+      ln -s ${config.sops.secrets."machineId".path} $out
+    '';
+
+    persistence."/persist" = {
+      "/etc/nixos" = { };
+      "/var/lib/nixos" = { };
+      "/var/lib/systemd" = { };
+      "/var/log" = { };
+    };
+  };
+}