Implements a basic CLI using Typer, Rich, and Prompt Toolkit. I couldn't
work out how to propoerly mock/fake the Rich console or the prompt
session from Prompt Toolkit, so I created dummy functions to work around
them and just test the basic application flow rather than user inputs
and outputs to the terminal.
Linting checks are performed using Ruff, Mypy, and Pydocstyle. Code
formatting is performed using Black and Isort. A Makefile is also added
with linting and formatting commands for convenience.
This commit implements a basic interface to hold a conversation with
OpenAI's GPT models via their API, using OpenAI's Python SDK. In
addition to this interface, the commit incorporates Pydantic for
managing settings via environment variables.
Paul Harrison