allowUnsafeConfigurations option should be added:
There should only ever be 1 or 0 Arbiters. An Arbiter should only be used when the count of data nodes is an even number.
it shouldn't be possible to run less than 3 Pods cluster (3 psmdb OR 2 psmdb + 1 arbiter)
any amount of PSMDB Pods and Arbiters Pod allowed