Make AMI public for use by Customers

Description

This change makes the DLE AMI produced by packer public so that it can be referenced by any AWS account. This is important because it allows customers to reference our published AMI without needing to run packer and build the AMI themselves from this repository.

I believe that longer term, we should make running packer a part of the CI process for the DLE itself. When new versions are published, packer should run and publish a new, versioned, AMI for customers to use and reference.