[FIX] base_vat: new dutch vat number verification

Steps to reproduce:
- install contacts and vat number validation
- setup your company country to "Netherlands"
- go to contacts > add a company > try to add a dutch vat number
 (NL264077921B03)

Previous behavior:
Proper vat numbers are considered unvalid and raise a ValidationError

Current behavior:
Specific check added for dutch vat numbers

Related:
http://kleineondernemer.nl/index.php/nieuw-btw-identificatienummer-vanaf-1-januari-2020-voor-eenmanszaken
https://business.gov.nl/regulation/using-checking-vat-numbers/
http://www.pruefziffernberechnung.de/U/USt-IdNr.shtml



opw-2166380

closes odoo/odoo#43081

X-original-commit: b7a82684a311d736dfffd822c2fce8896104b96d
Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>
Co-authored-by: Nicolas Martinelli <nim@odoo.com>