Implement a high-performance backup mechanism for the HyperShift OADP plugin that ensures data consistency while maintaining cluster availability.

Design doc: https://docs.google.com/document/d/1zIor04wVvZukruaHr3iz9XJBbKh0akzkGEq86aHyPRo/edit?tab=t.ekw0ujiqg0xs#heading=h.mccc0wnss45f 

Problem Statement

Currently, the hypershift-oadp-plugin implementation prevents critical day-two operations (autoscaling, node provisioning) for 6-8 minutes per snapshot, often resulting in 20-30 minutes total per backup cycle. For customers requiring hourly backups, this translates to over 2 hours of daily downtime for cluster operations.

Epic Acceptance Criteria

• Pre-backup hooks are implemented using OADP job hooks to execute etcdctl snapshots directly to disk
• Reconciliation pause is eliminated entirely
• Day-two operations (autoscaling, node provisioning) remain functional during backup windows
• Disk-based etcd snapshots are successfully used for Persistent Volume backups
• Solution maintains data consistency equivalent to current backup approach
• Implementation supports both Azure and AWS HCP environments
• Documentation and runbooks are complete for operational teams

Scope

In Scope

• OADP pre-backup hook implementation for etcdctl snapshot execution
• Remove reconciliation pause during backup operations
• Maintaining availability of critical day-two operations during backups
• Disk-based etcd snapshot integration with PV backup process
• Data consistency validation and testing
• Support for Azure ARO HCP and AWS ROSA HCP platforms

Out of Scope

• Other cloud providers
• Complete redesign of the etcd backup/restore architecture

Parent Feature

This epic implements OCPSTRAT-2802 "Optimize Hypershift Reconciliation During OADP Backups".