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

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

java/google/registry/config/RegistryConfig.java

@@ -463,6 +463,17 @@ public final class RegistryConfig {
       return config.gSuite.outgoingEmailDisplayName;
     }
 
+    /**
+     * Returns the Google Cloud Storage bucket for storing Beam templates and results.
+     *
+     * @see google.registry.billing.GenerateInvoicesAction
+     */
+    @Provides
+    @Config("apacheBeamBucketUrl")
+    public static String provideApacheBeamBucketUrl(@Config("projectId") String projectId) {
+      return String.format("gs://%s-beam", projectId);
+    }
+
     /**
      * Returns the Google Cloud Storage bucket for ICANN transaction and activity reports to
      * be uploaded.