🥔✨ `Marketplace`: `Tax` Collection and Compliance

[zspencer]

• https://github.com/zinc-collective/convene/issues/831
• https://github.com/zinc-collective/convene/issues/1324
• https://github.com/zinc-collective/convene/issues/1326

Use Cases

• [x] 🥔 Seller sets TaxRates
  • [x] 🥔 As a %age of Product#price
  • [ ] 🌱 As a fixed amount per unit
  • [x] 🥔 TaxRates are shared across a Spaces Marketplaces
  • [x] 🥔 Seller associates TaxRates to Products
• [x] #1469
• [x] 🥔 Shopper pays Taxes
• [x] #1655

[zspencer]

I got a chance to speak with Adrionna Fike, the Board member at NoBAWC who worked at Mandela up until last year. The lowdown was:

1. There are city and state level sales taxes
2. Most sales taxes are collected from the customer, but some sales taxes are collected in part from the customer and the seller (i.e. the sugary foods tax)
3. Some products may be covered under multiple sales-taxes (i.e. bottled beverages > 16oz have a tax and a deposit fee)

For now, we'll likely want to allow a Space to define the SalesTax they collect across all Marketplaces, for example:

• Sales Tax (City of Oakland): 6%
• Bottle Deposit (State of California): $0.10
• Tobacco Tax (State of California): 13%

And each Product can then be associated to multiple taxes on the Marketplace::ProductsController#edit

[zspencer]

Do we want to group the taxes with the products when showing them? Or show them on a per-tax-rate basis? Right now we do:

Product A
Product B
Taxes Total
Delivery Fee
Total

but maybe it would make sense to organize it like:

Product A
  (Product A Tax)
Product B
Product C
  (Product C Tax)
Sub Total
Delivery Fee
Taxes 
Total

or

Product A
Product B
Product C
Product Total

Tax Rate A
Tax Rate B
Tax Rate Total

Delivery Fee

Total