[FLINK-38857][Model] Add docs for Triton inference model

[featzhang]

What is the purpose of the change

This PR adds comprehensive documentation for the Triton inference model in Flink SQL, enabling users to perform real-time model inference by calling NVIDIA Triton Inference Server from Flink.

The documentation introduces how to define, configure, and use Triton-backed models in Flink SQL, covering common inference scenarios as well as advanced production use cases.

What is the change

• Add a new Triton model documentation page under docs/connectors/models
  • Overview of Triton integration and supported features
  • End-to-end SQL examples for model creation and inference
  • Advanced configurations (authentication, headers, batching, compression, priority)
  • Examples for array-type inference and stateful / sequence models
• Add corresponding Chinese documentation to keep EN / ZH docs consistent
• Extend existing SQL documentation to reference Triton models:
  • CREATE MODEL syntax
  • ML_PREDICT usage for model inference

Why is the change needed

Triton is a widely used, high-performance inference serving system supporting multiple ML frameworks.
Providing first-class documentation for Triton model integration helps users:

• Integrate online model inference into Flink SQL pipelines more easily
• Understand supported configuration options and best practices
• Adopt Flink as a unified platform for real-time data processing and AI inference

How was this change tested

• Documentation-only change
• Verified SQL examples and configuration options for correctness and consistency

Does this PR introduce any user-facing change

Yes.
This PR introduces new user-facing documentation describing how to use Triton inference models in Flink SQL.

Checklist

• Documentation updated (English and Chinese)
• SQL examples provided
• No backward compatibility impact
• No code or runtime behavior changes

[flinkbot]

CI report:

• 5a0c7fb Azure: SUCCESS

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