Gpt-trainer-api

Added
- Added test cases and improved flow.

Added
- Handled 400 bad request to show the respons on error raise.

Added
- Added `stream_message` method to `MessageAPI`:
- Supports real-time streaming of chatbot responses from the GPT Trainer API.
- Returns concatenated streamed response as a single string.
- Added full support for managing session messages, including:
- Listing messages (`list_messages`).
- Deleting individual messages (`delete_message`).
- Bulk deleting messages (`bulk_delete_messages`).

Changed
- Improved error handling and documentation for `MessageAPI`.

---

Added
- Implemented full support for Data Sources, including:
- File upload
- Adding QA pairs
- Adding URLs
- Bulk deletion of sources
- Re-scraping URLs.
- Unified API client `GPTTrainerAPI` for easy access to all APIs.

Changed
- Improved `source_api.py` with additional methods for managing data sources.

---

Added
- Initial release of `gpt_trainer_api`:
- Chatbot management.
- Agent management.
- Session creation and message handling.
- Basic data source management.