refactor: split server modules into smaller more manageable files

modules/nixos-modules/server/jellyfin/impermanence.nix

@@ -0,0 +1,66 @@
+{
+  lib,
+  config,
+  ...
+}: let
+  jellyfin_data_directory = "/var/lib/jellyfin";
+  jellyfin_cache_directory = "/var/cache/jellyfin";
+in {
+  config = lib.mkIf (config.services.jellyfin.enable && config.host.impermanence.enable) {
+    fileSystems."/persist/system/jellyfin".neededForBoot = true;
+
+    host.storage.pool.extraDatasets = {
+      # sops age key needs to be available to pre persist for user generation
+      "persist/system/jellyfin" = {
+        type = "zfs_fs";
+        mountpoint = "/persist/system/jellyfin";
+        options = {
+          atime = "off";
+          relatime = "off";
+          canmount = "on";
+        };
+      };
+    };
+
+    assertions = [
+      {
+        assertion = config.services.jellyfin.dataDir == jellyfin_data_directory;
+        message = "jellyfin data directory does not match persistence";
+      }
+      {
+        assertion = config.services.jellyfin.cacheDir == jellyfin_cache_directory;
+        message = "jellyfin cache directory does not match persistence";
+      }
+    ];
+
+    environment.persistence = {
+      "/persist/system/root" = {
+        directories = [
+          {
+            directory = jellyfin_data_directory;
+            user = "jellyfin";
+            group = "jellyfin";
+          }
+          {
+            directory = jellyfin_cache_directory;
+            user = "jellyfin";
+            group = "jellyfin";
+          }
+        ];
+      };
+
+      "/persist/system/jellyfin" = {
+        enable = true;
+        hideMounts = true;
+        directories = [
+          {
+            directory = config.services.jellyfin.media_directory;
+            user = "jellyfin";
+            group = "jellyfin_media";
+            mode = "1770";
+          }
+        ];
+      };
+    };
+  };
+}