Move VAT rates from Monies to Pyvat

[nicomollet]

Is your feature request related to a problem? Please describe.
Following:

• https://github.com/wp-media/monies/issues/213

Some VAT rates are handled in Monies but centralized VAT rates in Pyvat library makes more sense.

• Europe VAT zone: uses VIES to validate VAT, each country has its own rate, B2B are exempt
  • France exception: B2B are not exempt and pay 20% (handled by seller setting in Pyvat library)
• Other countries handled in Monies:
  • Switzerland CH: B2B and B2B pay same tax 8.1%
  • Norway NO: B2C 25%, waiting confirmation if/how to exempt B2B
  • Great Britain UK/GB: validates against HMRC UK tax service
  • Egypt EG: B2C 14%, TODO exempt B2B
• Other countries handled in Pyvat (unmerged PR):
  • Canada CA: tax 0% until we have confirmation of region based rates, and if B2B exemption
• Currently not handled by anything:
  • France "region/country" Monaco MO: VAT 20% same as France, B2B should not be exempt
  • France "region/country" Reunion RE+GP+MQ: VAT 8.5% has a specific rate, B2B should not be exempt

Describe the solution you'd like

• Move logic for Other countries from Monies to Pyvat
• Handle France "regions/countries" MO+RE+RE+GP+MQ, same as France (check % above), make sure B2B can't be exempt no matter the VAT number
• Don't put any non EU country in the EU_COUNTRIES setting: GB, CH, NO, GP, RE, MQ, CA, EG are not EU VAT zone.

Describe alternatives you've considered
N/A
Additional context
N/A

[mostafa-hisham]

📔 Scope a solution

In Pyvat we have

• VatRules Class handles VAT rates.
• Registry Class handles vat_number checks. By default, it returns false if the country doesn't have a registry class (B2B will not be exempted).

We need to do the following:

🪜Development steps

• Europe VAT (VIES): no changes, already handled

• Great Britain UK/GB (HMRC): no changes, already handled

• Egypt EG (B2B): edit EgyptRegistry to return true (B2B will be exempt without real validation).

• Switzerland CH:

  • Create ChVatRules as we did for EgVatRules with VAT 8.1%
  • Create SwitzerlandRegistry to return false (B2B will not be exempt)

• Canada CA:

  • Create CaVatRules as we did for EgVatRules with VAT 0%
  • Create CanadaRegistry to return true (B2B will be exempt without real validation).

• Norway NO:

  • Create NoVatRules as we did for EgVatRules with VAT 25%
  • Create NorwayRegistry to return true (B2B will be exempt without real validation until we get confirmation) @nicomollet, please tell us if we should exempt B2B like other countries or not until we get final confirmation.

• Monaco MO:

  • Create MoVatRules as we did for EgVatRules with VAT 20%
  • Create MonacoRegistry to return false (B2B will not be exempt)

• DOM [RE, GP, MQ]:

  • Create DomVatRules as we did for EgVatRules with VAT 8.5%
  • Create DomRegistry to return false (B2B will not be exempt)

🧪 How to test?

• manual test
• add test cases in pyvat tests if possible

✳️ Grooming confidence level:

ok

👥 Can be peer-coded:

No

🥊 Is a refactor needed in that part of the codebase?

no

⏳Effort estimation:

S to M (if we created tests and make CI run them)