[WIP][kv_offload] Decouple store policy and request lifecycle from the scheduler#40625

hickeyma wants to merge 5 commits intovllm-project:mainvllm-project/vllm:mainfrom

hickeyma:add-sched-side-policy-extrhickeyma/vllm:add-sched-side-policy-extrCopy head branch name to clipboard