KEP-6011: Add ControllerGetNodeInfo and NodeGetID CSI RPCs for controller-side node info retrieval

This KEP proposes two new CSI RPCs to enable node topology and capacity
information retrieval from the controller side, eliminating the need for
cloud API credentials on worker nodes:

- NodeGetID: Returns only the node identifier without cloud API access
- ControllerGetNodeInfo: Fetches topology and capacity from controller side

Benefits:
- Security: Node components no longer require cloud API credentials
- Scalability: Controller can aggregate and cache API calls for large clusters
- Accuracy: Controller-side VolumeAttachment info enables accurate non-CSI attachment detection

Depends on CSI spec PR kubernetes#603: container-storage-interface/spec#603

Author: huww98

keps/prod-readiness/sig-storage/6011.yaml

@@ -0,0 +1,14 @@
+# "prod-readiness-approvers" group:
+# - deads2k
+# - johnbelamaric
+# - jpbetz
+# - soltysh
+# - wojtek-t
+# - kannon92
+kep-number: 6011
+alpha:
+  approver: TBD
+beta:
+  approver: TBD
+stable:
+  approver: TBD