[Feature] Add support to control 'Boot diagnostics' of VMSS via AKS agent pools

[mkilchhofer]

Is your feature request related to a problem? Please describe.

We at @swisspost miss the feature to directly connect to the AKS workers via serial console (boot diagnostics) in case of an issue. The AKS agent pool does neither enable boot diagnostics on the Virtual machine scale set by default nor does it support to configure it inside the Agent Pools.

Describe the solution you'd like The AKS agent pool supports configuration regarding boot diagnostics

Name	Type	Description
bootDiagnostics	BootDiagnostics	Boot Diagnostics is a debugging feature which allows you to view Console Output and Screenshot to diagnose VM status. NOTE: If storageUri is being specified then ensure that the storage account is in the same region and subscription as the VM.You can easily view the output of your console log.Azure also enables you to see a screenshot of the VM from the hypervisor.

Source: https://learn.microsoft.com/en-us/rest/api/compute/virtual-machine-scale-sets/create-or-update?tabs=HTTP#diagnosticsprofile

Describe alternatives you've considered

• Connect via SSH / Azure Bastion
• Connect via kubectl debug https://learn.microsoft.com/en-us/azure/aks/node-access

Additional context There were already similar issues in the past which were closed due to inativity:

• https://github.com/Azure/AKS/issues/1310
• https://github.com/Azure/azure-sdk-for-go/issues/5443