Support for rack aware scheduling

[anvinjain]

Is your feature request related to a problem? Please describe. Charts like those of bookkeeper and zookeeper do not provide for a way to ensure that pod placement is rack aware

Describe the solution you'd like Ability to configure appropriate label to use which can be used to get rack info and then ensuring that pods are not placed in the same rack. This should be optional.

Describe alternatives you've considered No clear alternatives.

Additional context Discussed this with @addisonj in a different chat.