Added a new method cloneable? to check if VMs/Templates can be cloned or not

issue #253
https://bugzilla.redhat.com/show_bug.cgi?id=1122712
Well, if that were the case, we'd need to add specs for a lot of other classes that are sub-classes of VmOrTemplate: MiqTemplate and Vm which are direct sub-classes, but then all of those sub-classes, such as TemplateInfra, TemplateCloud, VmInfra, and VmCloud. Then sub-classes of those sub-classes. By putting the spec on VmOrTemplate, you're ensuring that any instance of a VmOrTemplate type (which includes sub-classes) will behave properly, and if you override the method definition, then that is when it should be tested by itself.