Fix Rubydoc comments for Vcloud::Core::ConfigValidator

Move the Rubydoc comments intended for the Vcloud::Core::ConfigValidator class.

[Yard](http://yardoc.org/) was associating these comments to the `Vcloud` module; move them so that they appear under the `ConfigValidator` class. See [Rubydoc.info](http://rubydoc.info/gems/vcloud-core/Vcloud) for an example.

Also, fix the formatting for these comments.