Language information should be pulled from extra field key: vlaue pairs

[wlpotter]

For CBSS, we have switched to use Zotero's dedicated language field to record the language in which the item's title is expressed. This is to ensure the formatted bibls are capitalized correctly.

As a consequence, however, we have moved information related to the publication language(s) of the item to the extra field. The following keys should be used instead of Zotero's language field:

• PubLang contains a comma-separated list of ISO language codes that should populate the textLang element. The first should be the @mainLang attribute; the others should become a space-separated list for the @otherLangs attribute
• LangNote should become a note of type "language-note" and added to the biblStruct element -- following the analytic, monogr, and series element but before any refs or cited Ranges (cf. https://www.tei-c.org/release/doc/tei-p5-doc/en/html/ref-biblStruct.html)

[wlpotter]

The addition of textLang from the JSON language field was requested in biblia-arabica#16. Want to confirm that these alterations won't affect their process?

[wlpotter]

Note: I've added this as an option, if set in the config file

• including a <pub-lang>extra</pub-lang> element in the config will use the PubLang field for the publication language, otherwise it will use the language property of the JSON. This lets CBSS use the extra field without disrupting the other method

[wlpotter]

Done, with the old system preserved