Public preview: Mariner container optimized OS

Mariner is an open-source Linux distribution created by Microsoft and is now available for preview as a container host on Azure Kubernetes Service (AKS). Optimized for AKS, the Mariner container host provides reliability and consistency from cloud to edge across the AKS, AKS-HCI, and Arc products. You can deploy Mariner node pools in a new cluster, add Mariner node pools to your existing Ubuntu clusters, or migrate your Ubuntu nodes to Mariner nodes. To learn more about Mariner, see the [Mariner documentation](https://microsoft.github.io/CBL-Mariner/docs/#cbl-mariner-linux). **Why use Mariner** The Mariner container host on AKS uses a native AKS image that provides one place to do all Linux development. Every package is built from source and is validated, ensuring your services run on proven components. Mariner is lightweight, only including the necessary set of packages needed to run container workloads. It provides a reduced attack surface and eliminates patching and maintenance of unnecessary packages. At Mariner's base layer, it has a Microsoft hardened kernel tuned for Azure. Learn more about the [key capabilities of Mariner](https://microsoft.github.io/CBL-Mariner/docs/#key-capabilities-of-cbl-mariner-linux). * Azure Kubernetes Service (AKS) * Features * [ Azure Kubernetes Service (AKS)](https://azure.microsoft.com/en-gb/products/kubernetes-service/)