Comsumer Improvements (Default Branch, Invoke Commands, Updated README)

[bryanculver]

This repo's majority consumers are people looking to bake new cookies instead of developing updates to it. Therefore the default branch should be main which should have the latest releases of all cookies.

Developers are rarer and in the README.md we can call out a Contributing section where you're asked to checkout develop.

Additionally, an invoke command should be created to trigger the baking of a cookie as opposed to the current pattern of calling cookiecutter directly, think invoke bake where it will prompt you which cookie you want to bake and confirm which version of the cookie you are baking.

Lastly the README should be updated to inform the users of the above best practices.

[bryanculver]

Also poetry install instead of pip install cookiecutter