home: packages: add 'allowAliases', 'allowUnfree'

With [1], this should now be taken into account properly.

[1]: https://github.com/nix-community/home-manager/pull/4304

modules/home/packages/default.nix

@@ -6,6 +6,10 @@ in
   options.my.home.packages = with lib; {
     enable = my.mkDisableOption "user packages";
 
+    allowAliases = mkEnableOption "allow package aliases";
+
+    allowUnfree = my.mkDisableOption "allow unfree packages";
+
     additionalPackages = mkOption {
       type = with types; listOf package;
       default = [ ];
@@ -17,9 +21,15 @@ in
     };
   };
 
-  config.home.packages = with pkgs; lib.mkIf cfg.enable ([
-    fd
-    file
-    ripgrep
-  ] ++ cfg.additionalPackages);
+  config = lib.mkIf cfg.enable {
+    home.packages = with pkgs; ([
+      fd
+      file
+      ripgrep
+    ] ++ cfg.additionalPackages);
+
+    nixpkgs.config = {
+      inherit (cfg) allowAliases allowUnfree;
+    };
+  };
 }