Add new option to inject envoy container using sidecar feature provided by Kubernetes

[KMConner]

Is your feature request related to a problem?

I want to access services in AppMesh from CronJob containers.
Since envoy containers will not end automatically, the CronJob Pods never end even if the main container ends.

Describe the solution you'd like

Kubernetes provides sidecar container feature. (https://kubernetes.io/docs/concepts/workloads/pods/sidecar-containers/)
This feature will help use AppMesh with CronJobs.

So, I want feature to select two ways of sidecar injection.

• Add one more container to Pods (this is the current behavior)
• Add container using sidecar container feature provided by Kubernetes (mentioned earlier)