Support Chndoi, CNKI's Chinese DOI registrar

[AbeJellinek]

https://forums.zotero.org/discussion/119667/chndoi-add-item-from-china-doi-database
https://doi.org/10.16418/j.issn.1000-3045.2019.09.003

Unclear if these all have a common prefix (10.16418?) or if there's a machine-readable API; DOI.org returns HTML with no regard for the Accept header.

[doubanchan]

@jiaojiaodubai has realized a relatively efficient translator in CNKI.js.

also take a look at issue 347 in translators_CN/issues/347 (in Chinese).

Besides CNKI, there's another DOI registrar jointly operated by WanFang and ISTIC (Institute of Scientific and Technical Information of China).

[jiaojiaodubai]

DOIs point to CNKI has been resolved in translators_CN/CNKI.js (support access outside China mainland as well), other sites still in progress. In translators_CN, I have made a radical refactor for CNKI.js to support all item types in CNKI and its subsites.