add skip-to-filters link for admin tables

src/registrar/templates/admin/change_list.html

@@ -37,6 +37,8 @@
             for {{ search_query }}
         {% endif %}
     </h2>    
+    
+    <a class="usa-skipnav" href="#changelist-filter" aria-label="Skip to the filters section">Skip to filters</a>
 {% endblock %}
 
 {% comment %} Replace the Django ul markup with a div. We'll replace the li with a p in change_list_object_tools {% endcomment %}