core: Adding VdcObjectType, VdcActionType..

core: Adding VdcObjectType, VdcActionType and ActionGroup for external tasks

Change-Id: I1f2893b6c717c616b5adacab7e2070719fb4c2fa
Signed-off-by: Eli Mesika <emesika@redhat.com>
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=872719