Use Typer's echo for output in cli.py

[stratofax]

As recommended in [Logging HOWTO ](https://docs.python.org/3.8/howto/logging.html#basic-logging-tutorial) if you want to "Display console output for ordinary usage of a command line script or program" the "best tool for the task" is print(), or in this case, the Typer equivalents, echo or secho.

During development, using logging as a unified messaging and notification channel is extremely useful, especially considering pytest's support for logging -- see [Logging — pytest documentation](https://docs.pytest.org/en/6.2.x/logging.html).

For production code, however, using Typer's echo or secho may be the better choice, especially since Typer offers fine grained control over the formatting of the output string, including color.