Pydantic was used only for validating settings. Since we don't have any
really complex types there, we can easily do it manually. We would have
to upgrade to Pydantic V2 soon, and that means +6.5MB of dependencies,
so let's drop it and enjoy a smaller install venv.
Most CLI arguments can be now saved into the configuration profile JSON.
This also cleans up passing around some, but not all args, into various
classes and methods, instead of just passing all of settings.
