create a script bootstrap CLI

[ericgazoni]

Since creating new scripts/workers is going to be a repetitive task, we should automate as much as possible the amount of work required to have a working script.

Ideally reusing something like cookiecutter (or borrowing the logic) to generate:

• setup.cfg & setup.py
• requirements.txt
• scriptname/__init__.py
• scriptname/__main__.py
• README.md

It could be invoked as kirby new <scriptname> --type=script

type could be either script, sensor or task