Experimental support for S3 backend

[schmika]

[fitnycdigitalinitiatives]

Hello,

I was curious about what state of development this is in. We use your plugin in the conventional way, storing ocr files on our solr server, but we also already have all our ocr in our s3 storage so s3 support would be something we could benefit from.

Thanks and really appreciate all your work on this plugin.

-Joe

[jbaiter]

We're currently a bit blocked on this due to insufficient performance of the implementation. We're still researching on how to improve it and have some ideas, but due to other stuff going on at the moment, it's not likely to be done this year.