Automate plagiarism check submission and result retrieval via Turnitin's API

Steps

1. Authenticate by including the header 'Authorization: Bearer <API_KEY>' on all requests to the Turnitin Similarity API base URL
2. Create a submission by POST /api/v1/submissions with a JSON body containing owner (user ID), title, and submitter; note the returned submission id
3. Upload the file content by PUT /api/v1/submissions/<id>/original with the appropriate Content-Type (e.g., application/pdf or text/plain) and the file binary as the request body
4. Poll GET /api/v1/submissions/<id> until the status field changes from 'PROCESSING' to 'COMPLETE'; implement exponential backoff between polls
5. Request a similarity report by POST /api/v1/submissions/<id>/similarity with generation settings such as search_repositories and auto_exclude_self_matching_scope; then GET /api/v1/submissions/<id>/similarity to retrieve the overall_match_percentage once the report status is 'COMPLETE'