This allows validation of a yaml/json object against an openapi schema.
A lot more testing would be needed to validate the logic, and also this
is not plumbed in, so it can't be used by kubectl yet.
Get command now uses metadata x-kubernetes-print-columns, if present, in Openapi schema
to format output for a resource. This functionality is guarded by a boolean
flag 'use-openapi-print-columns'.