Resources prefixed with *kubernetes.io/ should remain unscheduled if they are not exposed on the node.

Currently, resources prefixed with *kubernetes.io/ get scheduled to any
node whether it's exposing that resource or not.

On the other hand, resources prefixed with someother.domain/ don't get
scheduled to a node until that node is exposing that resource (or if the
resource is ignored because of scheduler extender).

This commit brings the behavior of *kubernetes.io/ prefixed resources in
line with other extended resources and they will remain unscheduled
until some node exposes these resources.

This also includes renaming IsDefaultNamespaceResource() to
IsNativeResource().