feat: Add base url for client

[0x676e67]

This pull request includes several changes to add support for a base URL parameter in the Client class, enhance the WebSocket documentation, and update the related Rust structures. The most important changes include adding the base_url parameter, updating the Client class, and adding an example script demonstrating the new functionality.

Support for Base URL Parameter:

• rnet.pyi: Added base_url as an optional string parameter to the ClientParams class.
• src/param/client.rs: Added base_url field to the ClientParams struct and updated the FromPyObject implementation to extract this new parameter. [1] [2]

Enhancements to WebSocket Documentation:

• rnet.pyi: Enhanced the websocket method documentation in the Client class to include arguments, return values, and examples.

Example Script:

• examples/base_url.py: Added a new example script demonstrating how to use the base_url parameter with the Client class and perform a streaming request.