Update base image for terraform

Follow on to #20 (closed). The RKE2 base image used it over a year old and should be updated. We have 2 choices:

1. Rebuild the image using RHEL UBI 8.5 (or later)
2. Build a new image using CIS Amazon Linux 2 STIG Benchmark. This option is cheaper than a RHEL license and provides level 3 benchmarking.

Unfortunately, I think we may have lost the recipe on how to create the RKE2 image, so we may need to experiment