### What this PR does / why we need it? See RFC: https://github.com/vllm-project/vllm-ascend/issues/2470 This PR add a new kv connector for layer-wised kv transfer ### Does this PR introduce _any_ user-facing change? yes, a new kv connector is added. User can use layer wised feature now. ### How was this patch tested? - vLLM version: v0.11.0rc3 - vLLM main: https://github.com/vllm-project/vllm/commit/releases/v0.11.0 --------- Signed-off-by: leichao.lc <leichao139636@163.com> Signed-off-by: CaveNightingale <2859066733@qq.com> Signed-off-by: nwpu-zxr <zhouxuerong2@huawei.com> Signed-off-by: wangxiaoteng <wangxiaoteng@huawei.com> Signed-off-by: hanxinlong <50882499@qq.com> Signed-off-by: liziyu <liziyu16@huawei.com> Co-authored-by: CaveNightingale <2859066733@qq.com> Co-authored-by: nwpu-zxr <zhouxuerong2@huawei.com> Co-authored-by: wangxiaoteng <wangxiaoteng@huawei.com> Co-authored-by: hanxinlong <50882499@qq.com>