Opens a resumable upload session to send a picture, video or PDF (model#739: only kept on items whose reason accepts documents) of a repair item straight to the storage, so an upload cut by the connection goes on from the bytes already stored instead of starting again. PUT the file to url in chunks with Content-Range (a status query Content-Range: bytes */<size> answers how many bytes are stored), then confirm the upload with path so it can be referenced from customerImageNames when the repair is created. The session only accepts exactly size bytes and answers CORS requests for the origin of this request.