Copy wiki content to index page
Copy wiki content to index page

Copy the content from the main wiki page that is not covered
elsewhere in these docs to the index page.

Change-Id: I94b68b7a0117d08fc8aba961c6de728118ef794e

BjoernT/python-openstackclient,dtroyer/python-openstackclient,redhat-openstack/python-openstackclient,BjoernT/python-openstackclient,openstack/python-openstackclient,openstack/python-openstackclient,redhat-openstack/python-openstackclient,dtroyer/python-openstackclient