[Airiti] Rewritten to use BibTeX and to enable searching by DOI

We could use some improvements to detectWeb, but my Chinese is not up to the task (I didn't see anything obvious in the HTML). Test case 3 needs to be detected as thesis. (also, test case 2 used to be conference paper, but BibTeX says it's journal article. Not sure what it should be.

Supersedes the version from #632

Requires zotero/zotero#441 for better performance with multiple DOI searching (commented out for now)