Context

There are two prose tests for DRIVERS-2884 that requires starting a proxy server to intercept and forward messages.

Definition of done

1. Ensure that drivers-evergreen-tools PR #662 has been merged.
2. Modify driver Taskfile to add a step named “start-mongoproxy. Point that step at the drivers-evergreen-tools start-mongoproxy.sh script.
3. Create an evergreen function (e.g. “start-mongoproxy”) that invokes the new Taskfile step.
4. For every non-SSL, non-auth Evergreen task, add a pre-step or setup entry that calls the “start-mongoproxy” function. Ensure each of these tasks includes the MONGO_PROXY_URI variable in its environment (mongodb://127.0.0.1:28017/?directConnection=true).
5. Add a new MongoProxy client type to mtest