Add a class to manage integration test configuration

[elliottt]

In order to make the compute-sdk-test action reusable for other sdks, and to wrangle its current complexity, this PR adds a class to track configuration information and plumbs it through the tests. The next step will be to break up the test running logic in main.js so that it's possible to run one test at a time.

[jameysharp]

On the one hand, my inclination would be to take this in a different direction, namely:

• put as little logic in the GitHub Action as possible
• make each test responsible for all of its own setup; ideally each test would just be an arbitrary executable script, whether that's JS or shell or whatever's convenient
• factor out all the common stuff into importable or sourceable libraries and let the tests invoke whichever parts they need

On the other hand, I think this is an improvement over what's already there, so, 👍