A binary to run pylint and python unittests

[jlewi]

Create a binary to run pylint and python unittests.

• This will be used in our E2E test pipeline.

• Partial fix to results of lint test aren't reported in junit file used by gubernator #126 (lint results not reported in gubernator)

  • This binary creates junit files with junit files

• Partial fix to Run lint (Python, Go) as a presubmit test #53 (run pylint as a presubmit)

  • This provides a binary to run lint that will be incorporated into our E2E pipeline.

• Partial fix to Run python unittests as part of pre/post/periodic tests #101 (run python unittests as part of pre/post submit)

  • This PR provides a binary to run the unittests; subsequent PR will integrate it into Airflow.

[jlewi]

@jimexist Do you want to review this change?

[jlewi]

I'm going to take that as a no and go ahead and merge this. Happy to address any comments in upcoming PRs.