Deploy GHES on managed Kubernetes instance running on Packet

Documentation for setting up a Kubernetes instances on Package.

IMPORTANT: after separate attempts (standalone Kubernetes install and a minikube install) getting GHES to work on a self-managed Kubernetes cluster running on a Packet VM was abandoned due to an issue with the Container Storage Interface (CSI) plugin for Packet. A CSI plugin acts as an interface between Kubernetes and Packet’s storage services, enabling persistent volumes to be created and attached. See Issue #23: Volumes get created but mounting fails for more details.