[V1][Log] Add max request concurrency log to V1

[mgoin]

Ports over the Maximum concurrency for XXXX tokens per request: YYx log from V0

VLLM_USE_V1=1 vllm serve neuralmagic/Meta-Llama-3.1-70B-Instruct-quantized.w8a8 --max-model-len 2048 --gpu-memory-utilization 0.98
...
INFO 01-30 03:18:12 gpu_model_runner.py:848] Loading model weights took 67.7229 GB
INFO 01-30 03:18:25 backends.py:577] Using cache directory: /home/mgoin/.cache/vllm/torch_compile_cache/2b70b500a6/rank_0 for vLLM's torch.compile
INFO 01-30 03:18:25 backends.py:585] Dynamo bytecode transform time: 12.88 s
INFO 01-30 03:18:28 backends.py:309] Cache the graph of shape None for later use
INFO 01-30 03:19:07 backends.py:321] Compiling a graph for general shape takes 41.86 s
INFO 01-30 03:19:13 monitor.py:31] torch.compile takes 54.73 s in total
INFO 01-30 03:19:14 kv_cache_utils.py:395] # GPU blocks: 1381
INFO 01-30 03:19:14 kv_cache_utils.py:398] Maximum concurrency for 2048 tokens per request: 10.79x

[github-actions]

👋 Hi! Thank you for contributing to the vLLM project.
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