Add method to close all invoices with an invoice direct

When the charge_members_manually option is active there is no need for an
explicit balancing step. This new function allows to close_direct all
orders which have an assigned invoice, which is usually indication enough
to find orders which can be closed finally.

config/routes.rb

@@ -161,6 +161,8 @@ Foodsoft::Application.routes.draw do
           get :new_on_order_article_create
           get :new_on_order_article_update
         end
+
+        post :close_all_direct_with_invoice, on: :collection
       end
 
       resources :invoices do