Add support for importing data from OpenLibrary

[aethior]

Rel: #9 #108

I think it would be a good idea to add support for importing data from OpenLibrary.

OpenLibrary is the source of the books’ metadata, so it would be useful to make it easier to import reading data as well.

Regards!

[royto]

Export file is a CSV with columns

Work ID,Title,Authors,First Publish Year,Edition ID,Edition Count,Bookshelf,My Ratings,Ratings Average,Ratings Count,Has Ebook,Subjects,Subject People,Subject Places,Subject Times

Reading status is linked to column Bookshelf. Values are: Currently Reading, Want to Read and Already Read

ISBN is not part of the export