refactor: Use custom CSV export view

Remove dependency on djangorestframework-csv

breccia_mapper/templates/export.html

@@ -24,7 +24,7 @@
                 <td></td>
                 <td>
                     <a class="btn btn-info"
-                       href="{% url 'people:person.api.list' %}?format=csv">Export</a>
+                       href="{% url 'people:person.export' %}">Export</a>
                 </td>
             </tr>
 
@@ -33,7 +33,7 @@
                 <td></td>
                 <td>
                     <a class="btn btn-info"
-                       href="{% url 'people:relationship.api.list' %}?format=csv">Export</a>
+                       href="{% url 'people:relationship.export' %}">Export</a>
                 </td>
             </tr>
         </tbody>