Consider exposing core functionality so consumers can import/run it outside of CLI

[eecavanna]

Thoughts:

• Extract the outermost function signature (the one with the Typer stuff) into a separate module, called cli.py
  • The function in that new module will call a function in refscan.py, whose signature is a stripped down version of the original one (i.e. no Typer stuff)
  • Update the pyproject.toml file to specify the main command as the one in cli.py
• Considerations:
  • What to do with the existing print statements that were designed for CLI usage. Maybe have them rely on either (a) a function parameter that says whether we're in CLI mode or imported mode, or (b) a callback function that does the printing—which could be a noop when in imported mode