Refactory vat job and remove args.py. Also fix .gitlab-ci.yml.

The VAT job should be more straightforward to understand. The .gitlab-ci.yml should have all stages working with our new pipeline-runner images.

Tested with trigger in Mario:

• URL: https://code-ib-mario.staging.dso.mil/ironbank-tools/tools/trigger/-/jobs/216010
• Artifacts: mario-trigger.zip

Compare VAT job artifacts:

• ubi9-vat-job-artifacts.zip
• fluent-bit-vat-job-artifacts.zip