build(deps): Apple platform dependencies are minimized as much as possible

[0x676e67]

This pull request introduces a new feature for supporting Apple platform's network device binding and includes several related changes across multiple files. The most important changes are listed below:

Dependency Management:

• Added apple-bindable-device dependency to Cargo.toml to enable the new feature for Apple platforms.
• Made the libc dependency optional for Apple platforms in Cargo.toml.

Feature Configuration:

• Updated the required-features for the client_chain example to include the new apple-bindable-device feature in Cargo.toml.

Code Modifications:

• Changed the network interface from "utun4" to "utun6" in the client_chain.rs example to reflect the new feature.
• Updated the cfg_bindable_device and cfg_non_bindable_device macros in src/lib.rs to conditionally include the new feature for Apple platforms. [1] [2]
• Modified the connect function in src/util/client/connect/http.rs to support the new feature for Apple platforms.