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
I think ideally, there would be a spec for ```#cloneable?``` in each of the corresponding files. So, spec/models/vm_vmware_spec.rb would have the spec for ```#cloneable?```, as would vm_redhat_spec.rb, vm_microsoft_spec.rb, etc. This will make it easier to change later, when I'm guessing the logic for all of these things is going to be different. Bottom line is: I would not think to look in vm_or_template_spec for tests that are testing other objects or sub-classes in this case.

For the cases where it is false, like ```template_redhat```, I don't think we need a test in the template_redhat_spec.rb file because that will be covered by the VmOrTemplate test, since it's just directly inheriting the method and not overwriting it.

Something simple like this, I think would suffice:
```ruby
describe "#cloneable?" do
  let(:vm_or_template) { VmOrTemplate.new }

  it "returns false" do
    expect(vm_or_template.cloneable?).to eq(false)
  end
end
```

@gmcculloug Is correct about the class method needing to be tested as well. I would structure the file like this:
```ruby
describe VmOrTemplate do
  describe ".cloneable?" do
    # Set up goes here

    # Tests for class method go here
  end
  
  describe "#cloneable?" do
    # Tests for instance method go here, which should be like the other code block above.
  end
end
```