feat: add tracing

[chriscasto]

Tracing enables the collection of some very useful information about how data moves through your application. When a user searches for listings, for example, tracing will capture the initial request into the ALB, follow it to the backend task that process it, tie it to the database query that gets executed, and then follow it back through the task and ALB to the user. Each step of the way it will collect information about how long each step takes and note any bottlenecks or errors. This information can be used to diagnose errors ("which step failed when I tried to load that page?") as well as troubleshoot slow requests and make educated decisions on where to implement performance optimizations.

AWS has a built-in service named X-Ray that provides tracing functionality with minimal instrumentation required, although you will likely need to add an X-Ray daemon to your ECS cluster that your services can send trace data to. It supports tracing through HTTP/HTTPS requests (frontend to backend, backend to third party, etc), database queries, and interactions with some AWS services like S3 and SQS.