Adds param to def create_attach_volume (wait_to_finish), default to true...

Issue: #18118 
In a nutshell, as far as I know you cannot attach a newly created volume to an instance until it's 'available'. Therefore, when _creating and attaching volumes_ we always need to _wait for the volume to finish_.

I've added an additional param to def *create_attach_volume* defaulted to True (in case for some reason you want to tell this to be False as well). This will obviously hand itself to *create_volume*, which now behaves as expected.