Add russian OGRN

[nvmbrasserie]

Add OGRN (Russian Primary State Registration Number) validation and formatting

Added a new module for validating and formatting Russian OGRN numbers.
Implemented validation for OGRN length, checksum, and federal subject code.
Added a normalization function to format OGRN into valid 13- or 15-digit numbers.
Introduced a helper function to calculate the OGRN control digit.
Added basic usage examples and doctests for OGRN validation.

https://docs.trellix.com/bundle/data-loss-prevention-11.10.x-classification-definitions-reference-guide/page/GUID-945B4343-861E-4A57-8E60-8B6028871BA1.html

[arthurdejong]

Hi @nvmbrasserie,

Thanks for your PR.

The link you provided no longer seems to work.

I did find https://ru.wikipedia.org/wiki/Основной_государственный_регистрационный_номер which seems to be the same format, but only the 13 digit variant. The 15 digit variant seems to be https://ru.wikipedia.org/wiki/Основной_государственный_регистрационный_номер_индивидуального_предпринимателя (OGRNIP).

I understand you combined checking of both formats in this module. I've updated the documentation to reflect this. I've also made some changes to the functions to match those of other modules within python-stdnum and cleaned up the tests a bit. I've also fixed the copyright header.

I've merged it as 1386f67.

[nvmbrasserie]

Hi @arthurdejong! Thank you for cleaning it up and merging!