feat: add the request sdk in dragonfly-client-util

[chlins]

This pull request introduces significant enhancements to the dragonfly-client-util crate, focusing on expanding its functionality and improving error handling. The main changes include the addition of new modules (request and selector), a comprehensive error handling system for request operations, and several new dependencies to support these features.

New modules and error handling:

• Added new modules: request and selector to dragonfly-client-util/src/lib.rs, laying the groundwork for extended request handling and selection logic.
• Introduced a robust error handling system in dragonfly-client-util/src/request/errors.rs, including a new Error enum and detailed error types (BackendError, ProxyError, DfdaemonError) for distinguishing between different failure scenarios in client operations.

Dependency updates:

• Added several new dependencies to Cargo.toml (such as tonic, reqwest-middleware, futures, thiserror, bytes, protobuf, hashring, tonic-health, local-ip-address, hostname, dashmap, and new dev-dependencies for testing/mocking), enabling gRPC support, advanced HTTP handling, error management, and improved testing capabilities.
• Moved the reqwest dependency from the main [dependencies] section to the workspace-managed section for better dependency management.

Description

Related Issue

Motivation and Context

Screenshots (if appropriate)

[codecov]

Codecov Report

❌ Patch coverage is 95.20000% with 42 lines in your changes missing coverage. Please review.
✅ Project coverage is 49.58%. Comparing base (8ff694f) to head (72e8a85).

Files with missing lines	Patch %	Lines
dragonfly-client-util/src/request/mod.rs	95.89%	26 Missing ⚠️
dragonfly-client-util/src/selector/mod.rs	94.53%	13 Missing ⚠️
dragonfly-client-util/src/request/errors.rs	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1333      +/-   ##
==========================================
+ Coverage   46.90%   49.58%   +2.67%     
==========================================
  Files          60       63       +3     
  Lines       15061    15936     +875     
==========================================
+ Hits         7065     7902     +837     
- Misses       7996     8034      +38     

Files with missing lines	Coverage Δ
dragonfly-client-util/src/request/errors.rs	0.00% <0.00%> (ø)
dragonfly-client-util/src/selector/mod.rs	94.53% <94.53%> (ø)
dragonfly-client-util/src/request/mod.rs	95.89% <95.89%> (ø)

... and 2 files with indirect coverage changes

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