[#75691732] Document vcloud-core public methods

> According to semver http://semver.org/ we should document the API
> (lower case should). We should document this by adding Yard
> documentation to public methods. See [#73962736] for an example.
Could give examples here? e.g. orgVdcNetwork, vdc (run vCloud Query to make sure you get the examples right). Reason I suggest this is that `type` could do with clarification.