Add end-to-end code to run Beam template from App Engine

This serves as proof-of-concept to verify we can use Beam for our invoice generation use case. Namely, it checks that we can:
- Deploy a Beam template to GCS
- Read from Bigquery within the template
- Run the template from App Engine

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=175755390

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

@@ -28,6 +28,7 @@ import google.registry.batch.MapreduceEntityCleanupAction;
 import google.registry.batch.RefreshDnsOnHostRenameAction;
 import google.registry.batch.ResaveAllEppResourcesAction;
 import google.registry.batch.VerifyEntityIntegrityAction;
+import google.registry.billing.BillingModule;
 import google.registry.billing.GenerateInvoicesAction;
 import google.registry.cron.CommitLogFanoutAction;
 import google.registry.cron.CronModule;
@@ -86,6 +87,7 @@ import google.registry.tmch.TmchSmdrlAction;
         BackendModule.class,
         BackupModule.class,
         BatchModule.class,
+        BillingModule.class,
         CloudDnsWriterModule.class,
         CronModule.class,
         DnsModule.class,