Update Katib ROCKs to 0.16-rc.1 for CKF release 1.8

[orfeas-k]

This issue tracks the process of updating Katib ROCKs to Katib's 0.16 for CKF release 1.8. For the process, we 're following our internal Kubeflow ROCK Images Best Practices that has a section about Upgrade of ROCK Images.

The changes that this process will introduce should match what the upstream has for version v0.16-rc.1.

[orfeas-k]

cert-generator

Upstream has consolidated the katib-cert-generator component into the katib controller. Thus, there is no Dockerfile for it in 0.16-rc.1. We should remove it from main and keep it in the katib-rocks branch for CKF 1.7 (we haven't cut that yet).

[orfeas-k]

katib-db-manager

db-manager Dockerfile has introduced the following changes

5d4
< ENV GRPC_HEALTH_PROBE_VERSION v0.4.15
21,24d19
< # Add GRPC health probe.
< RUN wget -qO /bin/grpc_health_probe https://github.com/grpc-ecosystem/grpc-health-probe/releases/download/${GRPC_HEALTH_PROBE_VERSION}/grpc_health_probe-linux-${TARGETARCH} \
<   && chmod +x /bin/grpc_health_probe
< 
28d22
< COPY --from=build-env /bin/grpc_health_probe /bin/

which is expected according to canonical/katib-operators#122 (comment). Thus, we will not introduce those changes in the ROCK.

[orfeas-k]

katib-ui-rock

We need to rewrite the ROCK due to it being based on the wrong dockerfile #32.

[orfeas-k]

grpc health checks

As discussed here, we 're following what was done upstream and removing the binary for health checks since

this type of ROCK images are not managed by charms. GRPC checks will be peformed by K8S on this images.