Add ExpandRecurringBillingEventsAction cron job

Note that this merely starts this MR on a daily schedule -- the billing queries that ultimately consume the synthetic OneTime events are filtering out the events at this time, so we're still relying on query-time expansion of Recurrings.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=144450565

java/google/registry/batch/ExpandRecurringBillingEventsAction.java

@@ -66,8 +66,6 @@ import org.joda.time.DateTime;
  * {@code cursorTime}) represents the inclusive lower bound on the range of billing times that will
  * be expanded as a result of the job (the exclusive upper bound being the execution time of the
  * job).
- *
- * <p>NOTE: This is not yet production ready and not configured to run.
  */
 @Action(path = "/_dr/task/expandRecurringBillingEvents")
 public class ExpandRecurringBillingEventsAction implements Runnable {

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

@@ -144,6 +144,17 @@
     <target>backend</target>
   </cron>
 
+  <cron>
+    <url><![CDATA[/_dr/task/expandRecurringBillingEvents]]></url>
+    <description>
+      This job runs a mapreduce that creates synthetic OneTime billing events from Recurring billing
+      events. Events are created for all instances of Recurring billing events that should exist
+      between the RECURRING_BILLING cursor's time and the execution time of the mapreduce.
+    </description>
+    <schedule>every day 03:00</schedule>
+    <target>backend</target>
+  </cron>
+
   <cron>
     <url><![CDATA[/_dr/cron/fanout?queue=export-snapshot&endpoint=/_dr/task/exportSnapshot&runInEmpty]]></url>
     <description>

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

@@ -155,6 +155,17 @@
     <target>backend</target>
   </cron>
 
+  <cron>
+    <url><![CDATA[/_dr/task/expandRecurringBillingEvents]]></url>
+    <description>
+      This job runs a mapreduce that creates synthetic OneTime billing events from Recurring billing
+      events. Events are created for all instances of Recurring billing events that should exist
+      between the RECURRING_BILLING cursor's time and the execution time of the mapreduce.
+    </description>
+    <schedule>every day 03:00</schedule>
+    <target>backend</target>
+  </cron>
+
   <cron>
     <url><![CDATA[/_dr/cron/fanout?queue=export-snapshot&endpoint=/_dr/task/exportSnapshot&runInEmpty]]></url>
     <description>

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

@@ -62,6 +62,17 @@
     <target>backend</target>
   </cron>
 
+  <cron>
+    <url><![CDATA[/_dr/task/expandRecurringBillingEvents]]></url>
+    <description>
+      This job runs a mapreduce that creates synthetic OneTime billing events from Recurring billing
+      events. Events are created for all instances of Recurring billing events that should exist
+      between the RECURRING_BILLING cursor's time and the execution time of the mapreduce.
+    </description>
+    <schedule>every day 03:00</schedule>
+    <target>backend</target>
+  </cron>
+
   <cron>
     <url><![CDATA[/_dr/cron/fanout?queue=export-snapshot&endpoint=/_dr/task/exportSnapshot&runInEmpty]]></url>
     <description>