Support for Fargate

[rnzsgh]

This PR adds support for Fargate. It is a separate path than the current app/Elastic Beanstalk.

The following features are added (fargate support only):

• Creates an ECR registry
• Creates a default ALB (support for http or https - pass an optional TLS ARN as a param)
• CodePipeline triggered by a specified/parameter branch in a GitHub repo (deploy uses ECS target)
• Auto scaling up and down based on service CPU utilization
• Optional support for database stack params set as environment variables to the container
• Optional support for Route 53 domain mapping to the ALB
• Creates a single service based on the repo passed