Restructure flake.nix for a simpler config for building different images off the same NixOS config.

nix/configuration/roles/zfs/default.nix

@@ -29,26 +29,40 @@ in
 {
   imports = [ ];
 
-  boot.zfs.devNodes = "/dev/disk/by-partuuid";
-
-  services.zfs = {
-    autoScrub = {
-      enable = true;
-      interval = "monthly";
+  options.me = {
+    zfs.enable = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      example = true;
+      description = "Whether we want to install zfs.";
     };
-    trim.enable = true;
   };
 
-  environment.systemPackages = with pkgs; [
-    zfs_clone_send
-    zfs_clone_recv
-    zfs_clone_resume
-  ];
+  config = lib.mkIf config.me.zfs.enable {
+    # Technically only needed when building the ISO because nix detects ZFS in the filesystem list normally. I basically always want this so I'm just setting it to always be on.
+    boot.supportedFilesystems.zfs = true;
 
-  environment.persistence."/persist" = lib.mkIf (!config.me.buildingIso) {
-    hideMounts = true;
-    directories = [
-      "/etc/zfs/zpool.cache" # Which zpools to import, the root zpool is already imported and does not need this cache file but this captures additional pools.
+    boot.zfs.devNodes = "/dev/disk/by-partuuid";
+
+    services.zfs = {
+      autoScrub = {
+        enable = true;
+        interval = "monthly";
+      };
+      trim.enable = true;
+    };
+
+    environment.systemPackages = [
+      zfs_clone_send
+      zfs_clone_recv
+      zfs_clone_resume
     ];
+
+    environment.persistence."/persist" = lib.mkIf (config.me.mountPersistence) {
+      hideMounts = true;
+      directories = [
+        "/etc/zfs/zpool.cache" # Which zpools to import, the root zpool is already imported and does not need this cache file but this captures additional pools.
+      ];
+    };
   };
 }