Add commands to create plugins using skeletons

See

• https://pypi.org/project/Cheetah3/
• https://pypi.org/project/template/
• https://pypi.org/project/Jinja2/
• https://pypi.org/project/Mako/

and

• https://pypi.org/project/click/ (https://github.com/click-contrib/sphinx-click)
• https://pypi.org/project/cleo/
• https://pypi.org/project/typer/