[DRAFT][Terraform - AKS] Enable workload auto-scaling using KEDA addon

[yelghali]

Kubernetes Event-driven Autoscaling (KEDA) is a single-purpose and lightweight component that strives to make application autoscaling simple and is a CNCF Incubation project.

It applies event-driven autoscaling to scale your application to meet demand in a sustainable and cost-efficient manner with scale-to-zero.

c.f https://learn.microsoft.com/en-us/azure/aks/keda-about

code scan check
workload_autoscalerprofile {
keda_enabled = True
}

from https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/kubernetes_cluster#keda_enabled