Payment date and comment #3

* adds payment-comment relation in NewPaymentForm
 * drops transfer note form field (may not be used anyway) and replace it with comment
 * adds/updates translations

intervention/templates/intervention/detail/includes/payments.html

@@ -31,7 +31,7 @@
                     {% trans 'Due on' %}
                 </th>
                 <th scope="col">
-                    {% trans 'Transfer comment' %}
+                    {% trans 'Comment' %}
                 </th>
                 <th scope="col">
                     {% trans 'Action' %}
@@ -44,7 +44,7 @@
                 <td class="align-middle">
                     {{ pay.amount|floatformat:2 }} €
                 </td>
-                <td class="align-middle">{{ pay.due_on }}</td>
+                <td class="align-middle">{{ pay.due_on|default_if_none:"---" }}</td>
                 <td class="align-middle">{{ pay.comment }}</td>
                 <td>
                     {% if is_default_member and has_access  %}