Support writing description on create with Amazon EC2 Builders

_This issue was originally opened by @jasonberanek as hashicorp/packer#8869. It was migrated here as a result of the [Packer plugin split](https://github.com/hashicorp/packer/issues/8610#issuecomment-770034737). The original body of the issue is below._

#### Feature Description

Set the Amazon AMI description at the creation of the image, which allows the value to be set without requiring the `ec2:ModifyImageAttribute` IAM policy.

The existing Amazon AMI builders support setting the description, however set it after the AMI is created using `ModifyImageAttribute` requests. Some business IT policies restrict `ec2:ModifyImageAttribute` permissions to avoid their staff accidentally or intentionally exposing internal AMIs to external parties. In those cases, Packer will still run as long as none of the features requiring `ec2:ModifyImageAttribute` are part of the template, but this also means it is impossible to apply description text to help with image review/discovery.

The `description` attribute on the AMI is available to be set at create time in all of the existing Amazon EC2 builders, so the implementation should be straightforward.

#### Use Case(s)

* Support defining AMI descriptions for relevant EC2 builders even when `ec2:ModifyImageAttribute` has not been given to the requesting account.