Operator should recreate StatefulSets when doing a rolling update

[diegosolisfr]

Recently we encountered the problem that Operator is not recreating the StatefulSets when performing a rolling update for the Druid version.

We receive:

Failed to update [druid-routers:StatefulSet] due to [StatefulSet.apps "druid-routers" is invalid: spec: Forbidden: updates to statefulset spec for fields other than 'replicas', 'template', and 'updateStrategy' are forbidden].

To bypass the issue we did the manual steps described in #76

[AdheipSingh]

This error is returned from the kubernetes statefulset controller, the operator cannot/will not change the default statefulset behaviour unless needed for a specific usecase.