[Docs] Hide the navigation and toc sidebars on home page (#22749)

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

docs/README.md

+---
+hide:
+  - navigation
+  - toc
+---
+
 # Welcome to vLLM
 
 <figure markdown="span">