Add DeprecatedMachineType runbook

docs/runbooks/DeprecatedMachineType.md

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+# DeprecatedMachineType
+
+## Meaning
+This alert fires when one or more Virtual Machines (VMs)  
+are using machine types that have been marked as deprecated (no  
+longer supported).
+
+## Impact
+
+**Running VMs**
+- Continue running but are using a deprecated machine type.
+- Newer nodes may not support this type, so the next live migration may  
+  fail or get stuck.
+- This can block node maintenance and disrupt high availability.
+
+**Stopped VMs**
+- No immediate issue while stopped.
+- When restarted, they may fail to schedule or get stuck if newer nodes  
+  no longer support the deprecated machine type.
+- This can prevent workloads from coming back online after maintenance  
+  or cluster upgrades.
+
+
+## Diagnosis
+The alert detects VMs using deprecated machine types.
+
+**Identify affected VMs**  
+   Use the alert description to locate VM names, namespaces, and nodes (if running).
+
+**Root Cause:**  
+The VM's `spec.template.spec.domain.machine.type` field is set to a type
+that has been marked as deprecated. This can happen due to:
+
+- VMs created before a machine type deprecation.
+- VM templates not updated after cluster upgrades.
+- Manual VM creation using old machine type references.
+
+## Mitigation
+Update affected VMs to use a supported machine type. You can:
+
+- Edit VM definitions individually by modifying the
+  `spec.template.spec.domain.machine.type` field.
+- Or, for a smoother and cleaner update of multiple VMs, use the
+  `kubevirt-api-lifecycle-automation` tool to transition all deprecated VMs
+  in one operation. This ensures consistent, automated migration and reduces
+  manual errors or downtime during cluster upgrades. See the documentation  
+  for details: [Updating multiple VMs](https://docs.redhat.com/en/documentation/openshift_container_platform/4.18/html/virtualization/managing-vms#virt-updating-multiple-vms_virt-edit-vms)
+
+
+**Important:** Plan and apply these updates before performing cluster
+upgrades to avoid VM restart failures or compatibility issues.
+
+<!--DS: If you cannot resolve the issue, log in to the
+link:https://access.redhat.com[Customer Portal] and open a support case,
+attaching the artifacts gathered during the diagnosis procedure.-->
+<!--USstart-->
+If you cannot resolve the issue, see the following resources:
+
+- [OKD Help](https://okd.io/docs/community/help/)
+- [#virtualization Slack channel](https://kubernetes.slack.com/channels/
+  virtualization)
+<!--USend-->