Katib API Needs Documentation

[jlewi]

Documenting the API in the proto file would be very helpful to understanding how Katib works.
https://github.com/kubeflow/katib/blob/master/pkg/api/api.proto

[jlewi]

@YujiOshima @gaocegege Any progress on this? Do you think we can get it done in time for 0.4 which we want to cut on Dec 17?

[YujiOshima]

@jlewi This is important. I will do this in this week.
/assign

[jlewi]

@YujiOshima Any progress on this? Do you think we could get it done this week as part of our 0.4 release?

[jlewi]

Here's how Kubernetes generates its docs
https://kubernetes.io/docs/contribute/generate-ref-docs/kubernetes-api/