modqueue: add order options; change default order to newest first.

* Add options for changing the order of the modqueue (newest first,
  oldest first, highest scoring first, lowest scoring first).

* Change the default order from oldest posts first to most recently
  flagged or uploaded posts first.

* Add an order:modqueue metatag to order by most recently flagged or
  uploaded in standard searches.

app/models/application_record.rb

@@ -11,7 +11,7 @@ class ApplicationRecord < ActiveRecord::Base
         extending(PaginationExtension).paginate(*args, **options)
       end
 
-      def paginated_search(params, defaults: {}, count_pages: params[:search].present?)
+      def paginated_search(params, count_pages: params[:search].present?, **defaults)
         search_params = params.fetch(:search, {}).permit!
         search_params = defaults.merge(search_params).with_indifferent_access