[Misc][Tools][Benchmark] Publish script to auto tune server parameters

[Chenyaaang]

Create a script to auto tune server parameter.

This script aims to tune the best server parameter combinations to maximize throughput for given requirement. The current server parameter combination is max_num_seqs and max_num_batched_tokens. It also supports additional requirement: e2e latency and prefix cache.

Use case:

1. Given input_len=1800, output_len=20, what's the best max_num_seqs and max_num_batched_tokens to get highest throughput?
2. If we have latency requirement to be lower than 500ms, what are the best server parameters?
3. If we want to reach 60% prefix cache, what are the best server parameters?

[github-actions]

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[yaochengji]

Thanks for you contribution, @Chenyaaang !

@mgoin @robertgshaw2-redhat how do you think about this PR? Is there any plan to support service level parameter auto-tuning in vLLM community?