Add a batched [] for DNS refreshing on host renames

This will replace the existing DnsRefreshForHostRenameAction.

This is stage one of a three stage migration process. It adds the new queue and
[] but doesn't call them yet. Stage two will cut over to using the new
functionality, and stage three will remove the old functionality.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=134793963

java/google/registry/env/sandbox/default/WEB-INF/cron.xml

@@ -51,6 +51,17 @@
     <target>backend</target>
   </cron>
 
+  <cron>
+    <url><![CDATA[/_dr/task/refreshDnsOnHostRename]]></url>
+    <description>
+      This job runs a mapreduce that asynchronously handles DNS refreshes for
+      host renames by mapping over all domains and creating DNS refresh tasks
+      for any domains that reference a renamed host.
+    </description>
+    <schedule>every 5 minutes synchronized</schedule>
+    <target>backend</target>
+  </cron>
+
   <cron>
     <url><![CDATA[/_dr/cron/fanout?queue=export-snapshot&endpoint=/_dr/task/exportSnapshot&runInEmpty]]></url>
     <description>