FR: File Uploads back to Zotero

[mergen3107]

This is rather a large Feature Request, so, I don't know if it feasible at all or not.
For now, this ticket can be used mainly for discussion.

The idea behind this is following:

1. Use Zotero to get an article from the Zotero account.
2. Read it in KOReader, make highlights, notes, write them into the file and save locally.
3. Upload the file as per Zotero API - File Uploads: https://www.zotero.org/support/dev/web_api/v3/file_upload
4. For consistency and clean order, have Zotero plugin only upload and maintain one such file. Maybe, with a suffix KOReader in the filename.

Now, there are still some problems in KOReader.

• Not all PDF viewers are able to display KOReader-written highlights: Highlighting issues koreader/koreader#12473 (comment) , but some of them are good: PDF annotation not saved on file in latest version koreader/koreader#12186 (comment)
• Not related to this FR directly, Statistics in KOReader might start over if highlights are written into file: The statistics of old read books have been reset koreader/koreader#11318 (comment)

P.S.
A side question, is there a particular reason why zotero/storage needs to be in koreader folder, and not in the HOME folder?
It doesn't directly affect my work flow (except occasionally in such cases: koreader/contrib#25), I am mostly just curious.