operator: Extend status to show difference between running and ready

[xperimental]

What this PR does / why we need it:

Currently the Loki Operator emits the ReadyCondition even when there are pods running but not ready yet. It looks like this causes error conditions to get lost by support and users, because they do not notice the pods in unready state.

This PR tries to fix this issue by only emitting the ReadyCondition when all LokiStack managed pods are ready and falling back to PendingCondition with a different message when all pods are running but some are missing their readiness check.

Which issue(s) this PR fixes:

No issue created (yet).

Special notes for your reviewer:

• An alternative implementation would be to introduce a new condition instead of including the "running but not ready" status in the PendingCondition.
• This PR also contains an unrelated change ("storage status is overwritten"). This can be split into a separate PR.

Checklist

• [x] Reviewed the CONTRIBUTING.md guide (required)
• [x] Tests updated
• [ ] CHANGELOG.md updated