Allow templates in extraInitContainers

[FlorianVielhauer]

Is your feature request related to a problem? Please describe.

I would like to use templates in the .Values.server.extraInitContainers to dynamically inject values into the extra init containers.

Describe the solution you'd like

Allow templates inside .Values.server.extraInitContainers by utilyzing the tpl function.

For example:

      initContainers:
        {{ tpl (toYaml .Values.server.extraInitContainers) . | nindent 8}}

Describe alternatives you've considered

Additional context

[pree]

Thanks @FlorianVielhauer
I think this is a good idea, but need to check what kind of issues could come up when changing this.