policy_options: support for prefix-list-override

geant/gap_ansible/roles/policy_options/templates/policy_statements.j2

@@ -26,6 +26,14 @@
             <prefix-list>{{ pl }}</prefix-list>
             {% endfor %}
           {% endif %}
+          {% if entry.from.prefix_list_override is defined %}
+            {% for pl in entry.from.prefix_list_override %}
+            <prefix-list-override>
+                <prefix-list>{{ pl.name }}</prefix-list>
+                <type>{{ pl.type }}</type>
+            </prefix-list-override>
+            {% endfor %}
+          {% endif %}
           {% if entry.from.policy is defined %}
             <policy>{{ entry.from.policy }}</policy>
           {% endif %}