Support setting affinity rules

[fornhunkle]

Recent updates allow setting replicaCount for deployments but the templates don't support setting affinity rules. In my case I want the pods running on different nodes.

Is this something you would consider adding?

If so, I could have a go at creating a PR for it.

Something along the lines of this for each deployment that can set replicas:

spec:
  template:
    spec:
      {{- with .Values.uat.affinity }}
      affinity: {{ toYaml . | indent 6 }}
      {{- end }}