Feature request: High availability by envoy cross Kubernetes cluster

*Description*:
For some use cases, user want to the gateway runtime (envoy here) can be deployed in different Kubernetes cluster, by this deployment model, it can provide cross cluster high availability.

Base on this, at least need the envoy has cross cluster deployment, and better with the control plane also has cross cluster deployment ability.

Maybe it is a little similar as the istio control plane to manage multi Kubernetes clusters.