[1/N] Refactor nightly test structure (#5479)

### What this PR does / why we need it?
This patch is a series of refactoring actions, including clarifying the
directory structure of nightly tests, refactoring the config retrieval
logic, and optimizing the workflow, etc. This is the first step:
refactoring the directory structure of nightly to make it more readable
and logical.

- vLLM version: v0.13.0
- vLLM main:
5326c89803

Signed-off-by: wangli <wangli858794774@gmail.com>

tests/e2e/nightly/multi_node/config/DeepSeek-R1-W8A8-A2.yaml

@@ -0,0 +1,57 @@
+test_name: "test DeepSeek-R1-W8A8 on A2"
+model: "vllm-ascend/DeepSeek-R1-0528-W8A8"
+num_nodes: 2
+npu_per_node: 8
+env_common:
+  VLLM_USE_MODELSCOPE: true
+  HCCL_BUFFSIZE: 1024
+  SERVER_PORT: 8080
+  OMP_PROC_BIND: false
+  OMP_NUM_THREADS: 10
+
+
+deployment:
+  -
+    server_cmd: >
+      vllm serve vllm-ascend/DeepSeek-R1-0528-W8A8
+      --host 0.0.0.0
+      --port $SERVER_PORT
+      --data-parallel-size 4
+      --data-parallel-size-local 2
+      --data-parallel-address $LOCAL_IP
+      --data-parallel-rpc-port 13399
+      --no-enable-prefix-caching
+      --max-num-seqs 16
+      --tensor-parallel-size 4
+      --max-model-len 36864
+      --max-num-batched-tokens 6000
+      --enable-expert-parallel
+      --trust-remote-code
+      --quantization ascend
+      --gpu-memory-utilization 0.9
+      --enforce-eager
+      --speculative-config '{"num_speculative_tokens": 1, "method":"mtp"}'
+      --additional-config '{"enable_weight_nz_layout":true}'
+
+  -
+    server_cmd: >
+      vllm serve vllm-ascend/DeepSeek-R1-0528-W8A8
+      --headless
+      --data-parallel-size 4
+      --data-parallel-rpc-port 13399
+      --data-parallel-size-local 2
+      --data-parallel-start-rank 2
+      --data-parallel-address $MASTER_IP
+      --no-enable-prefix-caching
+      --max-num-seqs 16
+      --tensor-parallel-size 4
+      --max-model-len 36864
+      --max-num-batched-tokens 6000
+      --enable-expert-parallel
+      --trust-remote-code
+      --quantization ascend
+      --gpu-memory-utilization 0.9
+      --enforce-eager
+      --speculative-config '{"num_speculative_tokens": 1, "method":"mtp"}'
+      --additional-config '{"enable_weight_nz_layout":true}'
+benchmarks: