feat: Transistor patch#23

This MR contains the following new features:

feat: install cloudwatch agent when json configs are present

Previously introduced in feat: install cloudwatch agent when json config... (!26 - closed).

feat: remove hardcoded region us-east-1 from the aws/internal module

The hard-coded occurrences of us-east-1 has been getting in the way when a region other than us-east-1 is being used for the runner-manager.

The MR replaces occurrences of us-east-1 under modules/aws/internal/ec2/manager/, while preserving the default region to us-east-1.

ref: https://gitlab.com/gitlab-com/gl-infra/gitlab-dedicated/team/-/issues/3380+