RFE: clarify "current" for MachineConfigPool status.configuration

The current property description is:

configuration represents the current MachineConfig object for the machine config pool.

But in a 4.12.0-ec.4 cluster, the actual semantics seem to be something closer to "the most recent rendered config that we completely leveled on". We should at least update the godocs to be more specific about the intended semantics. And perhaps consider adjusting the semantics?