[CI][Doc] Optimize multi-node CI (#3565)

### What this PR does / why we need it?
This pull request mainly do the following things:
1. Add a doc for multi-node CI, The main content is the mechanism
principle and how to contribute
2. Simplify the config yaml for more developer-friendly
3. Optimized the mooncake installation script to prevent accidental
failures during installation
4. Fix the workflow to ensure the kubernetes can be apply correctly
5. Add Qwen3-235B-W8A8 disaggregated_prefill test
6. Add GLM-4.5 multi dp test
7. Add 2p1d 4nodes disaggregated_prefill test
8. Refactor nightly tests
### Does this PR introduce _any_ user-facing change?

### How was this patch tested?


- vLLM version: v0.11.0rc3
- vLLM main:
17c540a993

---------

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

tests/e2e/nightly/multi_node/config/models/DeepSeek-V3.yaml

@@ -26,10 +26,6 @@ disaggregated_prefill:
 
 deployment:
   -
-    local_index: 0
-    master_index: 0
-    headless: false
-    env_extend:
     server_cmd: >
         vllm serve "vllm-ascend/DeepSeek-V3-W8A8"
         --host 0.0.0.0
@@ -66,10 +62,6 @@ deployment:
         }'
 
   -
-    local_index: 1
-    master_index: 0
-    headless: true
-    env_extend:
     server_cmd: >
         vllm serve "vllm-ascend/DeepSeek-V3-W8A8"
         --host 0.0.0.0