Improve code security/integrity

[bjones1]

Improve code security/integrity by deploying/fixing unit tests, test coverage, linters, code formatters/beautifiers, adding types (mypy/TypeScript) to the existing codebase.

• Integrate linting -- see a647b8c.
• Integrate black
• Add code coverage
• Add type checking

[bjones1]

Closing -- all tasks complete.