refactor: split server modules into smaller more manageable files

modules/nixos-modules/server/immich/fail2ban.nix

@@ -0,0 +1,26 @@
+{
+  lib,
+  config,
+  pkgs,
+  ...
+}: {
+  config = lib.mkIf (config.services.fail2ban.enable && config.services.immich.enable) {
+    environment.etc = {
+      "fail2ban/filter.d/immich.local".text = pkgs.lib.mkDefault (pkgs.lib.mkAfter ''
+        [Definition]
+        failregex = immich-server.*Failed login attempt for user.+from ip address\s?<ADDR>
+        journalmatch = CONTAINER_TAG=immich-server
+      '');
+    };
+
+    services.fail2ban = {
+      jails = {
+        immich-iptables.settings = {
+          enabled = true;
+          filter = "immich";
+          backend = "systemd";
+        };
+      };
+    };
+  };
+}