move some nixos configuration to ./nixos/modules and ./nixos/configurations. try to find a good arch to conbine home-manager and nixos modules.

users/home-manager/firefox.nix

@@ -1,4 +1,4 @@
-{ pkgs, ... }:
+{ pkgs, firefox-addons, ... }:
 {
   programs.firefox = {
     enable = true;
@@ -9,8 +9,8 @@
     profiles.default = {
       name = "default";
       isDefault = true;
-      extensions = with pkgs.nur.repos; [
-        rycee.firefox-addons.immersive-translate
+      extensions = with (pkgs.callPackage firefox-addons { }); [
+        immersive-translate
       ];
       search = {
         force = true;