Setup macOS CI for unit tests

[Andrewangeta]

Using GH actions macOS runner, to test transactions we need to setup a cluster locally through the installed mongoDB without using docker. Docker isn't officially installed on macOS and there's some weirdness when installing it via a separate action.

We should ideally build a script that manually starts the mongod instance and sets up the cluster manually before we run the tests.
This article should provide some good steps and serve as a starting point.