Add e2e test frame work and doctest

[Yikun]

What this PR does / why we need it?

Add quickstart doctest

Does this PR introduce any user-facing change?

no

How was this patch tested?

• CI passed
• Run /vllm-ascend/tests/e2e/run_doctests.sh
  Related: [Bug]: Fail to start vllm under /workspace #725

[Yikun]

# PWD: /__w/vllm-ascend/vllm-ascend
if [ ! -d /workspace/vllm-ascend/tests/doctest ]; then
  echo "Warning: the doctest path doesn't exists, copy now"
  cp -r tests/doctest /workspace/vllm-ascend/tests/
fi
cd /workspace
./vllm-ascend/tests/doctest/run_tests.sh

Info: ====> Start Quickstart test
Info: ====> Start simple_test
Traceback (most recent call last):
  File "<string>", line 1, in <module>
AttributeError: module 'vllm' has no attribute '__version__'

The test results are as expected: https://github.com/vllm-project/vllm-ascend/actions/runs/14743092958/job/41385215566?pr=730

[Yikun]

The CI will be failed as expected, because the infra image are using default imagePullPolicy: if you omit the imagePullPolicy field, and you specify the tag for the container image that isn't :latest, the imagePullPolicy is automatically set to IfNotPresent.

Offline discuss with @pkking , the infra imagePullPolicy should be changed to Always: every time the kubelet launches a container, the kubelet queries the container image registry to resolve the name to an image [digest](https://docs.docker.com/engine/reference/commandline/pull/#pull-an-image-by-digest-immutable-identifier). If the kubelet has a container image with that exact digest cached locally, the kubelet uses its cached image; otherwise, the kubelet pulls the image with the resolved digest, and uses that image to launch the container.

[1] https://kubernetes.io/docs/concepts/containers/images/#imagepullpolicy-defaulting
[2] https://kubernetes.io/docs/concepts/containers/images/#image-pull-policy

(update 0501) Discuss with @ppking, we can use ENV_HOOK_TEMPLATE_PATH to enable podTemplate to set image policy in infra.

[wangxiyuan]

ready for review now?

[Yikun]

ready for review now?

Yes, it‘s ready, pls help to review, I will take a final look and merge it after your +1.