Update Cloudformation Template, replace EC2 Launch Config with Launch Template

[jj22ee]

Issue #, if available:
AWS::AutoScaling::LaunchConfiguration is deprecated in favor of AWS::EC2::LaunchTemplate
See also: https://docs.aws.amazon.com/autoscaling/ec2/userguide/migrate-to-launch-templates.html

Description of changes:
Replace AWS::AutoScaling::LaunchConfiguration with AWS::EC2::LaunchTemplate

Testing:

• Created all resources in new Cloudformation stack
  https://docs.aws.amazon.com/xray/latest/devguide/scorekeep-tutorial.html#xray-gettingstarted-deploy

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[mwunderl]

I was able to create the stack and use the application.
Stack deletion failed after trying to delete the AWS::ECS::Service resource which timed out after 30 minutes.
Have you been able to delete?

[jj22ee]

Stack deletion failed after trying to delete the AWS::ECS::Service resource which timed out after 30 minutes.
Have you been able to delete?

To fix this:

1. In ECS console, go to Amazon Elastic Container Service > Clusters > scorekeep-cluster > Infrastructure
2. Select the instance, and select the deregister button.
3. Retry delete Cloudformation Stack

This is an existing issue (before sample app broke) where Cloudformation (or CDK) cannot delete an ECS service due to the instance not being drained.

• See ECS resource fails to delete when bringing the stack down. aws-scalable-big-blue-button-example#79
• (aws-ecs): Can't delete a stack with ASG Capacity providers aws/aws-cdk#14732
• (aws-ecs): hanging on deleting a stack with ASG capacity provider aws/aws-cdk#18179

We need to update AWS docs to ask customers to manually drain or deregister their ECS ec2 instance first before deleting the stack.

[mwunderl]

OK not a great experience for your customers trying to figure that out. Suggest following this example and using a Lambda function to clean up the compute resources.
aws/aws-cdk#14732 (comment)