[Feature Request] Async support for REST API

Currently, the Binance Python SDK relies on the synchronous `requests` library for its REST API operations. This makes it challenging to integrate with asynchronous Python applications and frameworks.

- Please consider adding support for async REST API operations to the SDK, such as by providing an async client or refactoring key functionality to use an async HTTP library (e.g., `httpx`, which supports both sync and async).
- This enhancement would greatly benefit developers who need high concurrency with Binance services but cannot use WebSocket.
- Maintaining backwards compatibility with synchronous usage would be ideal.

Thank you for considering this feature!