Task: Add liveness/readiness probes

[frodopwns]

The initial health checking probe was removed in #1198 to avoid issues where the Kubelet could not connect to the health endpoint on some clusters. The initial check was only doing a naive check anyway. We should regroup and investigate what these endpoints should actually do in order to ensure the operator is functioning and the reintroduce the code changes.

[babbageclunk]

We should check how to do this in controller-runtime and whether we can add custom health logic.

[matthchr]

We still think this is worth investigating. @super-harsh was looking at this some