feat(rust): build Rust documentation

[yangxk1]

Describe the enhancement requested

This issue proposes to establish comprehensive documentation for the Rust bindings, referring to the precedent of the Python documentation efforts (see issue #802 and @apache/incubator-graphar-website/issues/55).

The following tasks are included:

1. Rust Usage Documentation

   • Create user-facing documentation for Rust usage at /docs/libraries/rust/.
   • Document installation, basic usage, and code examples to help users get started with the Rust interface.

2. Rust API Documentation

   • Setup automated generation of Rust API documentation as part of the CI workflow.
   • Ensure the API docs are kept up-to-date and published alongside other language APIs if applicable.

3. Rust Implementation Status

   • Add and maintain a Rust implementation status document at docs/specification/implementation-status.md.
   • Clearly outline which parts of the GraphAr spec are supported, in progress, or planned for Rust.

Component(s)

Rust

[yangxk1]

related: #806