Unify the command line API

[kwinkunks]

Komodo currently consists of several different CLIs implemented by entry points (e.g. kmd, komodo-lint-maturity, etc) and at least one CLI in an unregistered standalone script (e.g. maintainer.py, see #291). All of the CLIs are implemented with argparse`, which has a few quirks (eg see #279) and has no built-in support for, e.g. rich terminal output.

It might be a nicer user experience, and more maintainable, to unify the API under one command (kmd or komodo, say), with the other functionality implemented as subcommands, e.g. kmd lint-maturity instead of komodo-lint-maturity.

Potentially we can start modernizing before refactoring, e.g. by making new commands/CLIs with a more flexible framework, e.g. click or rich-cli.