We couldn't copy to_unicode, to_bytes, to_str into module_utils because
of licensing. So once created it we had two sets of functions that did
the same things but had different implementations. To remedy that, this
change removes the ansible.utils.unicode versions of those functions.
You cannot call bytes(obj) to get a simple representation of obj on
Python 3! E.g. bytes(42) returns a byte string with 42 NUL characters
instead of b'42'.