Use shared jar to stage BEAM pipeline if possible (#1008)

* Use shared jar to stage BEAM pipeline if possible

Allow multiple BEAM pipelines with the same classes and dependencies to
share one Uber jar.

Added metadata for BulkDeleteDatastorePipeline.

Updated shell and Cloud Build scripts to stage all pipelines in one
step.

release/cloudbuild-nomulus.yaml

@@ -83,11 +83,13 @@ steps:
   - -c
   - |
     ./release/stage_beam_pipeline.sh \
-      init_sql_pipeline \
+      beam_pipeline_common \
+      ${TAG_NAME} \
+      ${PROJECT_ID} \
       google.registry.beam.initsql.InitSqlPipeline \
       google/registry/beam/init_sql_pipeline_metadata.json \
-      ${TAG_NAME} \
-      ${PROJECT_ID}
+      google.registry.beam.datastore.BulkDeleteDatastorePipeline \
+      google/registry/beam/bulk_delete_datastore_pipeline_metadata.json
 # Tentatively build and publish Cloud SQL schema jar here, before schema release
 # process is finalized. Also publish nomulus:core jars that are needed for
 # server/schema compatibility tests.