helm option for priorityClassName

[jpuskar]

Hi,
It would be great if the helm chart allowed priorityClassName to be set for the controller and speakers.

e.g.

spec:
  template:
    spec:
      priorityClassName: system-node-critical

Here's an example from another chart:
https://github.com/jetstack/cert-manager/blob/master/deploy/charts/cert-manager/templates/webhook-deployment.yaml#L44

[russellb]

cc @gclawes

[gclawes]

Do we want the option for separate priority classes between speaker and controller? That fits with the other options we have under .Values.controller and .Values.speaker.