Add enhancements: Advanced Retry Mechanism, Middleware System, and Enhanced Timeout Controls

[zinzied]

Summary of Implemented Features

1. Request/Response Middleware System:

• Created a flexible middleware framework for processing requests and responses
• Implemented common middleware classes (logging, timing, headers, etc.)
• Added support for custom middleware

2. Enhanced Timeout Controls:

• Added granular timeout controls for different phases of the request (connect, read, write)
• Implemented timeout strategies for retries (constant, linear, exponential)
• Integrated with the existing retry system

3. Advanced Retry Mechanism (previously implemented):

• Added support for different backoff strategies
• Implemented customizable retry conditions
• Added respect for Retry-After headers

[sigmavirus24]

https://requests.readthedocs.io/en/latest/dev/contributing/#feature-requests

Requests is under a perpetual feature freeze. As such, I'm not going to provide feedback on this pull request and am going to close it