Add ISO 15924 codes to orthographies

[justinpenner]

I was hoping the script names in each orthography would be machine-readable, as README_database.md mentions that script names should follow ISO 15924. However, when I match them up with the ISO standard, the following don't match:

Ancient South Arabian
Bamun
Bengali
Burmese
Chinese
Coptic/Nubian
Cree
Devanagari
Egyptian Hieroglyphs
Ge'ez
Ge'ez/Fidel
Georgian
Hangul
Hanja
Hanunoo
Inuktitut Syllabics
Kanji
Modern Yi
Mon-Burmese
N'Ko
Ojibwe Syllabics
Oriya
Sumero-Akkadian Cuneiforms
Tai viet
Tham
Tifinagh

I'm not sure the best way to solve this within Hyperglot, but it would be nice if the API exposed ISO codes for all scripts, or standard names to allow ISO codes to be looked up easily.

Since some of the non-ISO names listed above contain clarifying information (Ge'ez/Fidel, Inuktitut, Ojibwe, Modern Yi) that doesn't exist in the ISO names, maybe some could be moved to a script_preferred_name field, similar to what is already done for language names? Others that almost match the ISO (Devanagari, Hangul, Ge'ez, etc) could be corrected to match ISO 15924.