Cloudstack support for Advanced zones for any cloudstack cloud

I created a separate package next to the existing exo_scale code (cloudstack_exoscale_plugin vs cloudstack_plugin) The cloudstack plugin has support for security groups and advanced zones.

No extra unit tests yet, pinged uri on how to approach this, since the current implementation against live APi's seems tricky due to API/Secret key storage. I think we should move to stub based testing, but looking for your opinion too.