Hide un-subscribable services to logged users also

Completes 662bdfe6937a7acabaaa0817d8395e1122d2aeb6

costs/templates/costs/document_detail.html

@@ -47,7 +47,7 @@ un relevé.
 </p>
 
 <ul class="ui text container">
-{% for service in document.service_set.all %}
+{% for service in document.service_set.subscribables %}
   <li>
     <a href="{{ service.get_absolute_url }}">{{ service.name }}</a>
     ({{ service.get_prices.unit_consolidated_cost|price }} /mois)