Make Auth.SUPERUSER_SETUP_DELAY configurable

I would like to make SUPERUSER_SETUP_DELAY configurable for automated tests. I have tests that stand up a local cluster, and sometimes if I just run a single test class, the total execution time to stand up the (usually two) nodes and run the tests takes less than 20 seconds. I am running on fast hardware, so I can probably get by with a lower value in most cases, but maybe one of my teammates runs on slower hardware and needs a larger value.

I do not see this as a problem for production use. It would just be nice to have it configurable for dev environments.

Thanks