S3 upload: Bypass Discourse local storage

[supermathie (Michael Brown)]

这是一个活跃的项目：

A new era for file uploads in Discourse

You may have noticed over the past several months many commits related to uploads in Discourse core. This has been part of an overall effort within core to replace usages of jQuery file upload from our codebase, as part of an even broader overall effort to replace usages of jQuery itself from our codebase. jQuery file uploader is a very old project, and has been part of Discourse core since almost the beginning. I think I’ve used it for my whole career in other projects as well. But it’s time to…