Implement Pythonic API

[jamesaoverton]

COGS should have a Python API that's easy to use from Python. The CLI should use that API.

This is similar to ROBOT's distinction between command and operations. I like how I did it here:

• https://github.com/jamesaoverton/covic-db-tool-prototype/blob/master/src/covicdbtools/api.py
• https://github.com/jamesaoverton/covic-db-tool-prototype/blob/master/src/covicdbtools/cli.py