public class JcloudsProviderAndApiLoader
Retrieves a given jclouds provider or API. It stores the service-loader providers so as to
avoid repeatedly calling the ServiceLoader. This is fairly safe to do,
as they are normally only available if using a classic "java main" rather than an OSGi
container. For the latter, we query jclouds each time so that the list can be dynamic as
bundles are added/removed.