Refactor CLI to use subcommands

[stefmolin]

Describe your changes

• Increase minimum Python version to 3.11
• Mark existing pre-commit hook as deprecated (in the name) since it will now require a subcommand to run (meaning existing usage will break)
• Rework CLI to use subcommands for the three modes that Docstringify can be run in: check (look for missing docstrings), suggest (print templates for missing docstrings), and edit (inject docstrings templates into the code, with the option to overwrite the file). This allows the suggest and edit options to run in parallel since only the check option needs to run in serial (it needs to calculate the percentage of missing docstrings across the code base).
• Update CI workflow to test the new pre-commit hooks

Checklist

• Docstrings have been modified/created for any code changes.
• All linting and formatting checks pass (see the contributing guidelines for more information).