Adds Scanner Test Coverage and CI/CD Step

[cawalch]

Adds pytests for several scanners

• Adds a separate requirements.txt for local testing and development
• Adds github actions to install dependencies and run pytest for each PR
• Adds three example tests

Describe testing procedures
Install requirements.txt from src/python/requirements.txt
Run pytest

Sample output

It should not fail

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of and tested my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings

[phutelmyer]

• Some formatting changes
• Added additional docs to each proposed scanner test
• Updated README with usage instructions
• Added validators to requirements.txt