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.

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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 {