[Feature] ALB Controller Service Mesh Extension as AKS Addon

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

At the moment the Application Load Balancer Addon (needed for interacting with the Application Gateway for Containers) and the Istio Service Mesh can both be installed by an addon during cluster creation. This should be possible for the ALB Controller Service Mesh Extension aswell.

**Describe the solution you'd like**

A: Extension can be installed like the other addons
B: The exentsion gets installed as soon as both addons are activated

**Describe alternatives you've considered**

Installing the extension with helm, but this isn't as conventiend as a managed addon.