[TEST][DOC] Fix doctest and add system package installation (#1375)

### What this PR does / why we need it?
- Fix
[doctest](https://github.com/vllm-project/vllm-ascend/actions/workflows/vllm_ascend_doctest.yaml?query=event%3Aschedule)
- add system package installation
- Add doc for run doctests
- Cleanup all extra steps in .github/workflows/vllm_ascend_doctest.yaml
- Change schedule job from 4 ---> 12 hours

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?
- doctest CI passed
- Local test with
`/vllm-workspace/vllm-ascend/tests/e2e/run_doctests.sh`.

Signed-off-by: Yikun Jiang <yikunkero@gmail.com>

.github/workflows/vllm_ascend_doctest.yaml

@@ -30,8 +30,8 @@ on:
       - 'tests/e2e/common.sh'
       - 'tests/e2e/run_doctests.sh'
   schedule:
-    # Runs every 4 hours
-    - cron:  '0 */4 * * *'
+    # Runs every 12 hours
+    - cron:  '0 */12 * * *'
 
 # Bash shells do not use ~/.profile or ~/.bashrc so these shells need to be explicitly
 # declared as "shell: bash -el {0}" on steps that need to be properly activated.
@@ -65,37 +65,18 @@ jobs:
           cd /vllm-workspace/vllm
           git --no-pager log -1 || true
 
-      - name: Config OS mirrors - Ubuntu
-        if: ${{ !endsWith(matrix.vllm_verison, '-openeuler') }}
-        run: |
-          sed -i 's|ports.ubuntu.com|mirrors.tuna.tsinghua.edu.cn|g' /etc/apt/sources.list
-          apt-get update -y
-          apt install -y gcc g++ libnuma-dev git curl jq
-
-      - name: Config OS mirrors - openEuler
-        if: ${{ endsWith(matrix.vllm_verison, '-openeuler') }}
-        run: |
-          yum update -y
-          yum install -y gcc g++ numactl-devel git curl jq
-
-      - name: Config pip mirrors
-        run: |
-          pip config set global.index-url https://mirrors.tuna.tsinghua.edu.cn/pypi/web/simple
-
       - name: Checkout vllm-project/vllm-ascend repo
         uses: actions/checkout@v4
 
       - name: Run vllm-ascend/tests/e2e/run_doctests.sh
         run: |
           # PWD: /__w/vllm-ascend/vllm-ascend
+          # Make sure e2e tests are latest
           echo "Replacing /vllm-workspace/vllm-ascend/tests/e2e ..."
           rm -rf /vllm-workspace/vllm-ascend/tests/e2e
           mkdir -p /vllm-workspace/vllm-ascend/tests
           cp -r tests/e2e /vllm-workspace/vllm-ascend/tests/
 
-          # TODO(yikun): Remove this after conf.py merged
-          cp docs/source/conf.py /vllm-workspace/vllm-ascend/docs/source/
-
           # Simulate container to enter directory
           cd /workspace