Add `simple` example for the client library
Add `simple` example for the client library

The patch adds a new package containing a simple example of how the
client library is supposed to be used.

It shows the usage of the high-level API.

Change-Id: I6a31f4ac9bf0be5c82d71681abb0cac8b67d1d6b

openstack/python-zaqarclient