Rewrite infrastructure to use HTTP Gateway, Cloud Map, and EFS

This release rewrites the application infrastructure with these key changes:

• AWS API Gateway v2 (HTTP) in Proxy mode uses a private VPC-Link to provide SSL termination and proxying for the ECS service
• AWS Cloud Map is used for service discovery and container health checking
• AWS EFS is used as scalable and cheap persistent storage for both Ghost content (images, etc) and the sqlite database
• Security configuration was hardened in several ways

(now with proper tagged commit!)

Application load-balancer approach

This release was the initial implementation that used Aurora MySQL across the board and used application load balancers to do discovery, health checks, and load balancing for the ECS service.