Refactor nmdc_automation unit tests and add basic CI

[mbthornton-lbl]

This PR provides the following changes to nmdc_automation:

• Refactoring existing unit tests to fix import and other minor issues
• Refactoring some of the non-functional unit tests in jgi_file_staging unit tests - import and other minor issues only
• Implementing basic Build, Lint and Test workflow via GH Actions

Note: Some remaining tests in jgi_file_staging will still need repairs - the issues are more significant - primarily test fixtures with data that does not validate vs. the Sample model

[Michal-Babins]

All tests bar the jgi_file transfer code and the jawsapi are tested and pass. Github actions are succesful in setting up environment, linting, running pytests, and having completed.

Coverage badge only at 63% but gaps are known and will be fixed in future PR's. Current changes cover testing and github actions needed to implement workflow automation and import automation.