Remove associated AMI license before copying between regions

Removes the amazon-ebs publish region copy and replaces this with an explicit aws copy shell job so that we can disassociate the builder license from the build region AMI first.

The published AMI does not need to be associated with another license, as this will be handled by host resource groups when the AMI is used, and the license association is only required for this host scaling feature.

Adds an ami data source lookup for the base AMI so this works in any region (I tested in eu-west-1) and it makes upgrading the base image as simple as changing the wildcard pattern. See also Consider using AMI data sources rather than har... (gitlab-org/ci-cd/shared-runners/infrastructure#245)

Closes https://gitlab.com/gitlab-org/ci-cd/shared-runners/infrastructure/-/issues/243