Provision ECS Hello World (Nginx)

[aaroncarlucci]

This PR addresses #7 and includes:

• ECS cluster
• ECS service
• ECS task definition
• ALB and associated listener and target groups.

TODO:

• Implement an SSL certificate, listen on 443 and redirect port 80 traffic to HTTPS on the load balancer. Implement DNS and public SSL traffic on ALB #17
• Consider encrypting traffic between the load balancer and the app services - this might require building a custom docker image and self-signed certificate Encrypt traffic between ALB and ECS application #15
• Possibly decouple the ingress and egress rules from the security group definitions - that may cause consistency issues when infrastructure is destroyed or changed in some cases
• Iterate on hardening, documentation and testing
• Create issues for the above