Migrate docs from Sphinx to MkDocs (#18145)

Signed-off-by: Harry Mellor <19981378+hmellor@users.noreply.github.com>

docs/getting_started/installation/README.md

@@ -0,0 +1,20 @@
+---
+title: Installation
+---
+[](){ #installation-index }
+
+vLLM supports the following hardware platforms:
+
+- [GPU](gpu.md)
+    - [NVIDIA CUDA](gpu.md#nvidia-cuda)
+    - [AMD ROCm](gpu.md#amd-rocm)
+    - [Intel XPU](gpu.md#intel-xpu)
+- [CPU](cpu.md)
+    - [Intel/AMD x86](cpu.md#intelamd-x86)
+    - [ARM AArch64](cpu.md#arm-aarch64)
+    - [Apple silicon](cpu.md#apple-silicon)
+    - [IBM Z (S390X)](cpu.md#ibm-z-s390x)
+- [Other AI accelerators](ai_accelerator.md)
+    - [Google TPU](ai_accelerator.md#google-tpu)
+    - [Intel Gaudi](ai_accelerator.md#intel-gaudi)
+    - [AWS Neuron](ai_accelerator.md#aws-neuron)