add multi_npu_qwen3_dense tutorials (#4543)

### What this PR does / why we need it?

This PR adds tutorials for the Qwen3-Dense series models, including the
A2 and A3 series, and provides accuracy validation results.



- vLLM version: v0.12.0
- vLLM main:
vllm-project/vllm@ad32e3e

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Signed-off-by: wind-all <[email protected]>

Author: wind-all