Set ISO date in `itemFromCSLJSON()`

[dstillman]

For some reason we're using Zotero.Date.formatDate(), but I believe we use strToISO() in most site translators these days. Any reason not to change this?

var item = new Zotero.Item()
Zotero.Utilities.Item.itemFromCSLJSON(
    item,
    {
        type: 'article',
        "issued": {
        	"date-parts": [[ 2000, 3, 15 ]]
        }
        
    }
)
item

{
    "key": null,
    "version": null,
    "itemType": "preprint",
    "date": "March 15, 2000",
    "creators": [],
    "tags": [],
    "collections": [],
    "relations": {}
}

This resulted in a Chinese month being set ("四月 26, 2010") from ACM based on the browser locale:

https://forums.zotero.org/discussion/97683/bug-locale-issues-concerning-zotero-and-zotero-connector

(There was a separate parsing bug there that's been fixed.)