E-commerce settings in Git

Continuing on the git/e-commerce project.

I added .yml files for most settings:

• settings.yml: general settings
• tax-rates.yml: tax rules by country and region
• shipping-rates.yml: rates for shipping costs
• payment.yml: payment credentials
• email/*.md: templates for each email

I also improved the product model to support subscriptions and variants.

Code

https://github.com/joshnuss/git-ecom/compare/8ed606b2e1dc4ef38713ecdc6c4d432c455bace5…3b94358