cluster-autoscaler: add FAQ entry for the mechanics of "delete node"
cluster-autoscaler: add FAQ entry for the mechanics of "delete node"

This had me stumped for the better part of a day. While the
cluster-autoscaler "deletes" nodes, it does not actually delete the Node
object from the Kubernetes API.

In normal operations, with a well-configured cluster, this is a minor
point; however, when debugging why nodes do not get deleted, the
inconsistent terminology can be a major headache. This FAQ entry should
clarify the difference for anyone who needs to know.

Signed-off-by: Matthias Rampke <8e7be411ad89ade93d144531f3925d0bb4011004@soundcloud.com>

kubernetes/autoscaler,mmerrill3/autoscaler,bskiba/autoscaler,mmerrill3/autoscaler,bskiba/autoscaler,mmerrill3/autoscaler,kubernetes/autoscaler,kubernetes/autoscaler,bskiba/autoscaler,mmerrill3/autoscaler,kubernetes/autoscaler