Add a tools command to launch SQL validation job (#1526)

* Add a tools command to launch SQL validation job

Stopping using Pipeline.run().waitUntilFinish in
ValidateDatastorePipeline. Flex-templalate does not support blocking
wait in the main thread.

This PR adds a new ValidateSqlCommand that launches the pipeline and
maintains the SQL snapshot while the pipeline is running.

This PR also added more parameters to both ValidateSqlCommand and
ValidateDatastoreCommand:
- The -c option to supply an optional incremental comparison start time
- The -r option to supply an optional release tag that is not 'live',
  e.g., nomulus-DDDDYYMM-RC00

If the manual launch option (-m) is enabled, the commands will print the
gcloud command that can launch the pipeline.

Tested with sandbox, qa and the dev project.

core/build.gradle

@@ -707,10 +707,7 @@ createToolTask(
     'initSqlPipeline', 'google.registry.beam.initsql.InitSqlPipeline')
 
 createToolTask(
-    'validateSqlPipeline', 'google.registry.beam.comparedb.ValidateSqlPipeline')
-
-createToolTask(
-    'validateDatastorePipeline', 'google.registry.beam.comparedb.ValidateDatastorePipeline')
+    'validateDatabasePipeline', 'google.registry.beam.comparedb.ValidateDatabasePipeline')
 
 
 createToolTask(
@@ -797,15 +794,10 @@ if (environment == 'alpha') {
               mainClass: 'google.registry.beam.rde.RdePipeline',
               metaData : 'google/registry/beam/rde_pipeline_metadata.json'
           ],
-      validateDatastore  :
+      validateDatabase  :
           [
-              mainClass: 'google.registry.beam.comparedb.ValidateDatastorePipeline',
-              metaData: 'google/registry/beam/validate_datastore_pipeline_metadata.json'
-          ],
-      validateSql  :
-          [
-              mainClass: 'google.registry.beam.comparedb.ValidateSqlPipeline',
-              metaData: 'google/registry/beam/validate_sql_pipeline_metadata.json'
+              mainClass: 'google.registry.beam.comparedb.ValidateDatabasePipeline',
+              metaData: 'google/registry/beam/validate_database_pipeline_metadata.json'
           ],
   ]
   project.tasks.create("stageBeamPipelines") {