Allow for setting the 'serviceAccountName'

[kppullin]

What changes were proposed in this pull request?

This PR adds support for configuring a pod's serviceAccountName.

How was this patch tested?

This was tested through our terraform pipeline using a helm resource type.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}