Update package deployment process to move Publish-Dispatcher instances in ASG to standby

[mbloch1986]

Is your feature request related to a problem? Please describe.
Deploying an AEM package using the current deployment process may cause a Publisher instance to terminate during the deployment.

This can happen if the Publish-Dispatcher ALB Health Check keeps failing during the deployment, which will mark the Publish-Dispatcher as unhealthy. The ASG goes ahead and terminates the unhealthy Publish-Dispatcher. Due to the current orchestration process, the orchestrator will automatically terminate the paired publisher instance. As a result the infrastructure is unstable and the deployment process will fail. A rebuild of the AEM stack might be required.

To reduce the risk of an unstable AEM stack, we should update the deployment process to move the Publish-Dispatcher EC2 instances into standby, before deploying the packages.

Describe the solution you'd like
Updating the deployment process to move the Publish-Dispatcher into standby, before starting the deployment process. Either one by one or all at once.

Describe alternatives you've considered
Keeping the current process.