Run stress test prior to workshop

[rsignell-usgs]

We should run a stress test prior to using this for a workshop to see if https://esiphub.ndslabs.org can handle the expected number of attendees.

We can use this code:
https://github.com/yuvipanda/jupyterhub-loadtest

The number of users is set here:
https://github.com/yuvipanda/jupyterhub-loadtest/blob/master/loadtest/values.yaml#L12