Adapt S3 API code to use new multipart upload models

- Create and PutPart
- completemultipartupload
- upload part copy
- list_parts

src/api/s3/api_server.rs

@@ -27,6 +27,7 @@ use crate::s3::cors::*;
 use crate::s3::delete::*;
 use crate::s3::get::*;
 use crate::s3::list::*;
+use crate::s3::multipart::*;
 use crate::s3::post_object::handle_post_object;
 use crate::s3::put::*;
 use crate::s3::router::Endpoint;