Add pre-built FIPS AMI

**What would you like to be added**:
I'd like to be able to use a pre-built FIPS version of the AL2 EKS AMI provided by Amazon; AFAIK the spec for this is described in this [blog](https://aws.amazon.com/blogs/publicsector/enabling-fips-mode-amazon-linux-2/). I think this is required for both AMD64 & ARM64 but AMD64 support would do for now. I'd suggest the AMI name prefix of `amazon-eks-fips-node-`.

**Why is this needed**:
Everyone needing FIPS nodes needs to do the exact same thing which is the definition of toil and it should be easy to automate this as part of the AMI release process.

Start by locating the repository's Packer configuration and AMI release process, then compare the existing AL2 EKS AMI setup with the FIPS requirements in the linked AWS blog. Done means the release process produces a pre-built FIPS AMI with the proposed naming and at least AMD64 support.

Written by the indexing model from the issue text.