Support existing Service Account for the node ebs-csi in the Helm chart

[marlenepereira]

Is your feature request related to a problem? Please describe.
We use Pod Security Policies and have Service Accounts authorized to use specific policies. Installing the node Daemonset using the Helm chart does not allow specifying existing Service Account. So, we can't specify the Service Account that has the permissions to create the Pods.

Describe the solution you'd like in detail
The Helm chart provides an option to specify the name of an existing Service Account for the node service. This is already supported for other components deployed using the chart.

Describe alternatives you've considered
Authorize the default Service Account to use the Pod Security Policy for the node ebs-csi. This option is not good for us since other workloads might use that Service Account.