Load Test the API

During a discussion with @johnoliver we talked about how it would be good to add a load testing capability to the project. The goal of this being to understand the current throughput that the API can handle.

Some initial thoughts are:

it would be nice if the tests were driven from the OpenAPI docs
possibly use Gatling or JMeter

Start by reviewing the API's OpenAPI documentation and the existing project structure; no specific files or tests are named. Compare the suggested Gatling and JMeter approaches, then define how the load tests should be driven and how API throughput will be measured. Done means the project has a documented, repeatable way to load test the API and report its throughput.

Written by the indexing model from the issue text.