Enable configuring the affinity for the daemonset pods

[andrewmyhre]

Is your feature request related to a problem? Please describe.
In our clusters there are specific nodes that we want the Vault daemonset to select. In order to make this happen we are maintaining a fork of this Helm chart with a specific patch to enable configuring the affinity of the daemonset. We would like to see this added to the Helm chart so that we can use the official release rather than maintaining a fork.

Describe the solution you'd like
Add the following node to the values.yaml file schema:

daemonset:
  affinity: {}

And the following lines to csi-daemonset.yaml:

spec:
  template:
    spec:
      {{- if .Values.csi.daemonSet.affinity }}
      affinity:
        {{- toYaml .Values.csi.daemonSet.affinity | nindent 8}}
      {{- end }}

Describe alternatives you've considered
Forking the chart (current state)

Additional context