Include custom resource information also in operator namespace

We are currently treating the operator namespace as a special case and are not extracting information about the ECK custom resources in that namespace. This is done because we understand that `elastic-system` is a special namespace reserved for the operator and we do not recommend deploying workloads into that namespace.

In practice however we see users time and again deploying into `elastic-system`. We should therefore also extract full diagnostics from the operator namespace to avoid having to go back and having to ask for another diagnostic that declares `elastic-system` (or any other operator namespace) as a resource namespace.