feat(server): add a health check route before auth

[ddunkin]

Google Kubernetes Engine default ingress requires a health check route that returns a 200 response. If basic authentication is enabled, there is no route that can be used for a health check. This PR adds a /healthz route before the auth middleware to be used for health checks.

[patrickhulce]

thanks @ddunkin! where does /healthz come from? :)

• /ping
• /health
• /status

All come to mind as options, but if the z has significance I don't know of, happy to leave as-is :)

[ddunkin]

/healthz is a common convention because it's used in a lot of examples, at least in Kubernetes and Google Cloud. I don't think there's a significance to the z; the story I've heard is that long ago some Google internal service needed a health check and /health conflicted with an existing endpoint, so they tacked a z on the end and it stuck.

[patrickhulce]

cool, works for me then! a test that this new endpoint works would be much appreciated and we're good to merge :)

[patrickhulce]

thanks!