JCLOUDS-526: Removing Nova QuotaClassApi

The quota-classes API in Nova has been removed (and apparently never worked)
Creating a separate function to delete directories

Small refactoring to reuse some code.
Updating the Maven Site plugin version 3.1 -> 3.3

Also removing the stagingSiteURL parameter as we should not need
it for the site:deploy goal
ServerPredicates to make waiting easier.
Updated service types for OpenStack/Rackspace services