Implement the AWS::S3::Bucket resource type.

Implement the AWS::S3::Bucket resource type.

An attempt was made to make created bucket names readable and unique.
Names are of the format heat-<resource name>-<random hex>. eg:
heat-S3Bucket-b420d12d02e5d6e46f13

Only the swift v2 auth is currently supported, which means swift will need to
use keystone for auth. This may be a valid assumption for any environment that
is running Heat.

When DeletionPolicy is Delete then an attempt is made to delete the container,
but the stack will still be deleted if container delete fails.

Run the template S3_Single_Instance.template to give it a try.

Functional tests will be coming in a later change.

Change-Id: Ifa2c3c4fcbdb00a44f8c6b347a61f8e1735e8328