Pass terminationGracePeriodSeconds to RS containers

Following the forum thread: https://forums.percona.com/t/how-to-set-terminationgraceperiodseconds-for-statefulset/18894/5

We need to allow users to pass terminationGracePeriodSeconds (https://kubernetes.io/docs/concepts/containers/container-lifecycle-hooks/) to Replica Set containers.

This can help to cleanly shutdown the cluster in case of big data sets.