Alter vat alias for India

[unho]

According to https://www.oecd.org/tax/automatic-exchange/crs-implementation-and-assistance/tax-identification-numbers/India-TIN.pdf the "Permanent Account Number" is the TIN number.

[arthurdejong]

According to https://en.wikipedia.org/wiki/VAT_identification_number#VAT_numbers_of_non-EU_countries the GSTIN is the VAT number and according to https://en.wikipedia.org/wiki/Goods_and_Services_Tax_(India) GST has replaced VAT in 2017.

https://www.oecd.org/tax/automatic-exchange/crs-implementation-and-assistance/tax-identification-numbers/India-TIN.pdf does not talk about VAT but income tax.

While GST is not exactly VAT it appears to be closer than income tax.

Closing this but feel free to re-open if there is more information.

[unho]

@arthurdejong I do realize that. But if you want to go that route, then a new tin (or vatin) alias should be added so stdnum.vatin works. Also this will make third party software, like Odoo, to not properly work since they use stdnum vat aliases to identify the TIN validation for the countries.

This is something we have already talked a lot about, for example in #324 (comment) and #316