Update upgradeJob image to use Big-Bang Base Image

Rather than using an old gitlab/kubectl image, update the values for the upgradeJob to point to registry1.dso.mil/ironbank/big-bang/base:8.4 and ensure package and BigBang level CI are happy with change.

AC

• Upgrade-job template within package (runs on post-upgrade helm triggers) runs successfully using new image listed above.
• Kibana + Elasticearch apps are happy and healthy in testing and CI jobs are happy.
• Once new package version is merged in, issue CANNOT be closed until Big Bang level Merge Request to utilize new package tag/version has been merged in to the BigBang repo.
• Also ensure that the synker file includes the image - registry1.dso.mil/ironbank/big-bang/base:8.4