CLI for Extension Template

[gagb]

What feature would you like to be added?

Make it easier to create an extension by providing a template. E.g.,

autogen create-extension autogen-custom-extension

The result would be a directory of the format:

autogen-custom-extension/
    src/autogen_custom_extension/
        __init__.py
    tests/
    docs/
    pyproject.toml
    README.md

Why is this needed?

I tried creating a 3rd party extension for AutoGen. Creating the extension was easy and fun but creating the template took a large amount of time. Can we use cookiecutter to create a CLI that helps create the package template for users? cc @jackgerrits @ekzhu