Add details and clarify examples on casing
Add details and clarify examples on casing

This change adds some more detail to the roles section of the
casing documentation for keystone, as well as clarifying the
examples given for users and projects. Also added project tags
casing.

Change-Id: I55447c8b599ab48021bd95204c4bf3c5bc7e690c

mahak/keystone,openstack/keystone,openstack/keystone,mahak/keystone,openstack/keystone,mahak/keystone