Add a healthcheck endpoint to the controller

[kayneb]

Is your feature request related to a problem? Please describe. When configuring an NLB for the grant server Service, the only valid configuration to use is a simple TCP healthcheck, since there are no GET endpoints available, and no dedicated healthcheck. This results in a bunch of excess SSL error logs in the controller pod(s).

Describe the solution you'd like Add a healthcheck endpoint to the controller, e.g. GET /healthz

Additionally, configure a liveness and readiness probe on the pod, leveraging this endpoint

Describe alternatives you've considered There isn't really a better alternative

Additional context N/A