Add pod lifecycle

[fredsig]

Introduced pod lifecycle. When using the AWS Load Balancer Controller, deployments of pods trigger 5xx gateway errors when doing config changes, since the target group registration/deregistration of pods is out of sync with kubernetes service network orchestration (when an indexer pod gets terminated with a SIGTERM, it's done immediately, not giving enough time to drain connections from the ALB's target group, triggering 5xx errors to the client). Introducing a sleep time on indexers can help avoid this during pod termination (as a pre-stop action).

Related: https://medium.com/@imprintpayments/mastering-the-challenges-of-using-alb-ingress-in-kubernetes-8c28a8f826c5