### What this PR does / why we need it?
Refactor the multi-machine CI use case. The purpose of this PR is to
increase the ease of adding multi-machine CI use cases, allowing
developers to add multi-machine cluster model testing use cases
(including PD separation) by simply adding a new YAML configuration
file.
### Does this PR introduce _any_ user-facing change?
### How was this patch tested?
- vLLM version: v0.11.0rc3
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.0
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Signed-off-by: wangli <wangli858794774@gmail.com>
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