prettify file size format

Apply Jinja2 filter "filesizeformat" to filesize values

flask_admin/templates/admin/file/list.html

@@ -90,7 +90,7 @@
                 {% endif %}
             </td>
             <td>
-                {{ size }}
+                {{ size|filesizeformat }}
             </td>
             {% endif %}
             {% endblock %}