Add support for United Arab Emirates TIN

[unho]

• https://www.oecd.org/tax/automatic-exchange/crs-implementation-and-assistance/tax-identification-numbers/UAE-TIN.pdf

  Literally says N/A.

• https://tin-check.com/en/tin-check-united-arab-emirates/

  For individuals / entities: The TRN (TIN) is a unique 15-digit code provided by the FTA (Federal Tax Authority) of the UAE. This unique code is used as an ID for businesses and individuals for tracking taxes. TRN is also referred to as a VAT identification number in some parts of the world. Any business or individual that is registered under UAE VAT is issued a unique TRN number. And only the entities that have been registered under UAE VAT can charge VAT to customers. If you aren’t a “registrant”, charging VAT can land you in legal issues. Format: The TIN consists of 15 digits

• Note that it is part of the Gulf Cooperation Council, which it looks like provides some TIN framework?

• https://www.google.com/search?q=site%3A.ae+%22TRN%22