test(NODE-3049): drivers atlas testing

[durran]

Description

This PR makes the necessary changes in the driver for it to be able to be tested by Astrolabe.

What is changing?

• Adds a new task test:drivers-atlas-testing to run the unified test runner against the Astrolabe tests.
• Updates the test runner config to use the URI provided by Astrolabe when present in the environment.
• Creates an astrolabe results write to write the spec defined events.json and results.json
• Updates the entities map to handle new new entites for iterations, successes, events, failures, and errors.
• Creates a registry to handle mapping events between the unified client and the entities map.
• Adds a new unified operation loop, as defined per the Unified Test Format spec

Related drivers-atlas-testing changes: mongodb-labs/drivers-atlas-testing#173

Is there new documentation needed for these changes?

None

What is the motivation for this change?

NODE-3049

Double check the following

• Ran npm run check:lint script
• Self-review completed using the steps outlined here
• PR title follows the correct format: type(NODE-xxxx)[!]: description
  • Example: feat(NODE-1234)!: rewriting everything in coffeescript
• Changes are covered by tests
• New TODOs have a related JIRA ticket

[durran]

Since we have ClientEncryption in the driver now, I fixed this while I was in the area.

[baileympearson]

changes look good, just a few small suggestions