Azure: Auth Installer with Managed Identity from VM

User Story:

As a cluster admin I want to be able to:

• use the managed identity from the installer host VM (running in Azure)

so that I can

• install a cluster without copying credentials to the installer host

Acceptance Criteria:

Description of criteria:

• Installer (azure sdk) & terraform authenticate using identity from host VM (not client secret in file ~/.azure/servicePrincipal.json)
• Cluster credential is handled appropriately (presumably we force manual mode)

Engineering Details:

• Azure session: https://github.com/openshift/installer/blob/master/pkg/asset/installconfig/azure/session.go#L67-L75
• New `azidentity` supports managed identities: https://github.com/Azure/azure-sdk-for-go/blob/main/sdk/azidentity/MIGRATION.md#azidentity-3
• Creating a Managed Identity: https://learn.microsoft.com/en-us/azure/active-directory/managed-identities-azure-resources/qs-configure-cli-windows-vm
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