Disable Swift from the Undercloud

The goal of this proposal is to introduce the community to the idea of
disabling Swift on the TripleO Undercloud. Within this propose we intend
to provide a high-level overview of how we can accomplish this goal.

Swift is being used to store objects related to the deployment which are
managed entirely on the Undercloud. In the past, there was an API / UI to
interact with the deployment tooling; however, with the deprecation of the UI
and the removal of Mistral this is no longer the case. The Undercloud is
assumed to be a single node which is used to deploy OpenStack clouds, and
requires the user to login to the node to run commands. Because we're no longer
attempting to make the Undercloud a distributed system there's no need for an
API'able distributed storage service. Swift, in it's current state, is
under-utilized and carries unnecessary operational and resource overhead.