added initial impermanence module

modules/impermanence/default.nix

@@ -0,0 +1,41 @@
+{ lib, config, ... }: lib.mkIf config.withImpermanence {
+  environment.persistence."/persist" = {
+    enable = true;
+    directories = [
+      "/var/log"
+      "/var/lib/bluetooth"
+      "/var/lib/nixos"
+      "/var/lib/iwd"
+    ];
+    files = [
+      "/etc/machine-id"
+      "/etc/passwd"
+      "/etc/shadow"
+    ];
+
+    users.${config.username}= {
+      directories = [
+        "Documents"
+        "Pictures"
+        "Videos"
+        "Games"
+        "code"
+        { directory = ".local/share/keyrings"; mode = "0700"; }
+        ".local/share/direnv"
+      ];
+    };
+  };
+
+  boot.initrd = {
+    enable = true;
+    supportedFilesystems = [ "btrfs" ];
+
+    systemd.services.restore-boot = {
+      description = "Rollback btrfs rootfs";
+      WantedBy = [ "initrd.target" ];
+      requires = [
+        
+      ];
+    };
+  };
+}