Migrate off of statefulsets

[chrisseto]

Statefulsets and distributed systems like redpanda don't get along particularly well. In order to be able to more ergonomically, safely, and effectively run and administer redpanda clusters, we'll need to implement our own replication controller.

While this work is likely quite far off, it may be helpful to sketch out a CRD for a custom replication controller that can be massaged back into a statefulset so we don't find ourselves constantly fighting and updating our CRDs.

JIRA Link: K8S-200