Split Minnan into `nan-hans` , `nan-hant` , `nan-latn-pehoeji` (POJ), `nan-latn-tailo` (TL).
`nan-hani` , `nan-latn` were preserved for language converter codes.
Didn't use "`-poj`" , "`-tl`" as that might be distinguished with language/region codes.
NOTE: We should have separated translations for Pe̍h-ōe-jī (POJ) and Tâi-lô (TL).
* [x] Propose variant subtags to Ietf-languages mailing list
* [x] Variant subtags published on IANA Language Subtag Registry
* [x] Allow localization on translatewiki.net: https://gerrit.wikimedia.org/r/923637
* [ ] Add to Names.php: https://gerrit.wikimedia.org/r/876417
* [ ] Add to CLDR extension: https://gerrit.wikimedia.org/r/1009954
* [ ] Add to wikimedia-language-data
* [ ] Add to jquery.i18n
* [ ] Add to Wikifunctions
* [ ] Add to WikiLambda