Add podSpec/podTemplate/statefuSet field to override pod settings

[ebarped]

Many kubernetes operators add a field called podSpec/podTemplate that allows the user to override pod´s configuration with custom properties.

Examples:

• ECK uses podTemplate. example
• RabbitMQ uses override. example
• MongoDB uses statefulSet. example

This will be extremely useful, since we could add securityContext, dnsPolicy, dnsConfig, ...

My main case is to add dnsPolicy and dnsConfig, but this would allow the user to provide all these fields.
Another solution would be adding specific fields for securityContext, dnsPolicy, dnsConfig... to the CRD.

[TheRealHaoLiu]

I absolutely love this pattern