Soft move of deployer user to fargate service

[BSick7]

This PR adds the deployer user to the fargate service outputs contract. Because not all modules have been updated, this change is a forward-compatible change. Once all usage of fargate service module is upgraded to v0.11.0+, we can drop Deployer user from cluster outputs.

This should be released before releasing:

• https://github.com/nullstone-modules/aws-fargate/pull/5
• https://github.com/nullstone-modules/aws-fargate-service/pull/26