DRA Optional Node Operations

This KEP introduces Optional Node Operations to Dynamic Resource Allocation (DRA), allowing resource drivers to declare that node preparation and/or node unpreparation is not required for their devices. Currently, the kubelet assumes it must always coordinate with a node-local DRA driver via gRPC to prepare allocated devices before container start (NodePrepareResources), and to unprepare them during pod termination (NodeUnprepareResources). In some cases, node preparation or cleanup is a pure no-op. Requiring it forces administrators and vendors to deploy and maintain empty node-local drivers on every node, which introduces unnecessary operational complexity and risk. By introducing a SkipNodeOperations field to the ResourceSliceSpec and propagating it to the device allocation results at scheduling time, the kubelet can safely skip driver lookup and gRPC calls for devices that do not require these node-local actions.