Add `UPLOAD_RETRY` header to response on failed upload

[JosiahBull]

Issue

Description

As per the OpenAPI spec, in the event an upload files to the api, it should provide a new URL in a UPLOAD_RETRY header so the agent can try the upload again.

Tasks/General Thoughts

• Add UPLOAD_RETRY header
• Add test to ensure it isn't there on successful uploads
• Add test to ensure header appears after 1 failed attempt
• Add test to make sure that after 2 failed try it fails outright without a new header