Add more project templating/generator engines

[bollwyvl]

Elevator Pitch

While #18 includes some TLC for cookiecutter, there are more project templating tools. We should support more of them.

Motivation

Cookiecutter is great, though discoverability is a bit minimal. Other generators exist, with yeoman boasting a very large collection of discoverable endpoints.

Design Ideas

Yeoman documents their integration approach, but it may require some serious plumbing to get it to work. Perhaps a jlpm-style single-file package, potentially with a private (or at least Not Lab) node_modules for generators.

[bollwyvl]

https://github.com/copier-org/copier