VMs configured with VMHA should be migrated to another storage and kept running when the primary storage is put on maintenance.

### The required feature described as a wish

When a primary storage is put on maintenance, the systemVMs are migrated to another primary storage and all user VMs are stopped. The user VMs are migrated on demand when they are manually started.

This might not be the intended behaviour for Instances on which VMHA is enabled and which are expected to by highly available. We might add a global config which will control if the Instances configured with VMHA are automatically migrated and are kept running.

Creating this issue to discuss and track this feature request.

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Discussed on https://github.com/apache/cloudstack/issues/12215
From the documentation https://docs.cloudstack.apache.org/en/4.22.0.0/adminguide/storage.html#maintenance-mode-for-primary-storage
`it will stop all guests that have any volume on that storage device.`

Begin with the linked primary-storage maintenance documentation and issue #12215; the payload names no implementation files or tests. Clarify the global configuration and expected behavior for VMHA instances, including migration and keeping VMs running, then define tests or documentation that demonstrate the agreed result.

Written by the indexing model from the issue text.