[docs] add SYS_NICE cap & security-opt for docker/k8s (#24017)

Signed-off-by: Peter Pan <Peter.Pan@daocloud.io>
Signed-off-by: Peter Pan <peter.pan@daocloud.io>
Co-authored-by: Li, Jiang <bigpyj64@gmail.com>
Co-authored-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

docs/getting_started/installation/cpu/x86.inc.md

@@ -44,6 +44,7 @@ docker build -f docker/Dockerfile.cpu \
 # Launching OpenAI server
 docker run --rm \
             --security-opt seccomp=unconfined \
+            --cap-add SYS_NICE \
             --shm-size=4g \
             -p 8000:8000 \
             -e VLLM_CPU_KVCACHE_SPACE=<KV cache space> \