Consolidate expand billing events action into 'batch' package

Now it lives alongside the delete prober data action, as well as any future
batch/maintenance tasks that should run periodically.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=134435668

java/google/registry/module/backend/BUILD

@@ -22,7 +22,6 @@ java_library(
         "//java/google/registry/backup",
         "//java/google/registry/batch",
         "//java/google/registry/bigquery",
-        "//java/google/registry/billing",
         "//java/google/registry/config",
         "//java/google/registry/cron",
         "//java/google/registry/dns",

java/google/registry/module/backend/BackendModule.java

@@ -21,7 +21,7 @@ import static google.registry.request.RequestParameters.extractRequiredParameter
 import com.google.common.base.Optional;
 import dagger.Module;
 import dagger.Provides;
-import google.registry.billing.ExpandRecurringBillingEventsAction;
+import google.registry.batch.ExpandRecurringBillingEventsAction;
 import google.registry.request.Parameter;
 import google.registry.request.RequestParameters;
 import javax.servlet.http.HttpServletRequest;

java/google/registry/module/backend/BackendRequestComponent.java

@@ -21,7 +21,7 @@ import google.registry.backup.DeleteOldCommitLogsAction;
 import google.registry.backup.ExportCommitLogDiffAction;
 import google.registry.backup.RestoreCommitLogsAction;
 import google.registry.batch.DeleteProberDataAction;
-import google.registry.billing.ExpandRecurringBillingEventsAction;
+import google.registry.batch.ExpandRecurringBillingEventsAction;
 import google.registry.cron.CommitLogFanoutAction;
 import google.registry.cron.CronModule;
 import google.registry.cron.TldFanoutAction;