Local volumes: documentation improvements

[pebrc]

Part of #9247.

Overview

Add a dedicated section to the ECK documentation for local volume deployments, complementing the code changes in #9248, #9249, and #9250.

Content to cover

• Why PRE_STOP_SHUTDOWN_TYPE=remove is recommended for local volume deployments and how to size terminationGracePeriodSeconds
• How ECK's Node Shutdown API orchestration interacts with external node maintenance
• Using nodeSet renames for grow-and-shrink migrations
• PDB configuration for different maintenance scenarios
• Best practices for Karpenter, cluster-autoscaler, and managed K8s node pool upgrades (GKE, EKS, AKS)
• Troubleshooting guide for pods stuck in Pending due to orphaned PVCs
• Which local volume drivers handle their own PVC cleanup (e.g. TopoLVM)