[XPU] Add XPU Dockerfile and related docs (#1162)

Signed-off-by: Yan Ma <yan.ma@intel.com>
Signed-off-by: Daniel Huang <daniel1.huang@intel.com>
Co-authored-by: Daniel Huang <daniel1.huang@intel.com>

docs/getting_started/installation/README.md

@@ -5,4 +5,5 @@ vLLM-Omni supports the following hardware platforms:
 - [GPU](gpu.md)
     - [NVIDIA CUDA](gpu.md)
     - [AMD ROCm](gpu.md)
+    - [Intel XPU](gpu.md)
 - [NPU](npu.md)