Fix Swift Manifests for Proper Functionality

Previously, a swift cluster would not function when using COI
manifests.  This patch implements the following changes to support
a working swift cluster:

Core Manifest

1. enable/disable the creation of Swift Keystone endpoints based
on a user setting swift_proxy_address parameter in the site
manifest.

2. Removed the swift::keystone::auth class since this is passed to
the openstack::controller class and managed by the swift parameter.

3. Added the necessary swift parameters to the openstack::controller
class.

Site Manifest

1. Updated example definitions and Swift inline documentation.

2. Removed swift_user since exposing the swift_password is sufficient.
   Note: This can easily be changed at a future date.

3. Added required memcached parameters to openstack::swift::proxy
class.  Removed static 'admin' auth credentials.

4. Updated example storage node definitions.  Included 3 node
definitions since 3 nodes are the minimum number required to build
a swift ring.