feat: adding unit tests, removing unused arg from README

[bradmiro]

Adding unit tests:

• assert copy-data and project-setup workflows finished in the "SUCCEEDED" state
• assert BigQuery tables are created and nonempty
• assert exactly one Dataproc cluster is crated
• assert Dataproc cluster is in the "TERMINATED" (stopped) state

Updating README to remove a deprecated command line arg

[bradmiro]

/gcbrun