Deprecate auth plugins in favour of those from keystoneauth.

Change-Id: I8963ded9b68569717d7a6e30623ee78301b59a4a
Implements: bp deprecate-to-ksa

The oslo.config libraries are moving away from oslo-namespaced
packages.

Note that his requires oslo.config>=1.6.0

bp drop-namespace-packages

Change-Id: Ic0d4053875da0628f2359c109f2779d12aadc3eb

The Token/Endpoint options specify an instance method where the
expectation is a classmethod. This prevents the class being loaded from
config file or CLI.

The cfg module was not imported so loading plugins would raise an
AttributeError.

Change-Id: I33b4a8c181210d74d4779438afc1f918e06df85b

By marking the options as secret they don't get printed out in things
like the debug log when loading the application.

Change-Id: Iadab479a896bc4b1682ee8d207cc50a01dca8255

Provide a pattern for auth plugins to load themselves from a config
object. The first user of this will be auth_token middleware however it
is not likely to be the only user.

By doing this in an exportable way we are defining a single config file
format for specifying how to load a plugin for all services. We also
provide a standard way of retrieving a plugins options for loading via
other mechanisms.

Blueprint: standard-client-params
Change-Id: I353b26a1ffc04a20666e76f5bd2f1e6d7c19a22d

This auth plugin was initially created before get_endpoint was
available. Implement the get_endpoint method so that we can use the
plugin with relative URLs.

Closes-Bug: #1323926
Change-Id: Ic868f509e708ad29faf86ec5ceeab2a9c98a24fc

This is essentially the Admin token where your authentication will
always use a given token and have no means of querying information from
within that token blob.

Change-Id: Ia4317836d6fc1e62c65a1dcbd84c820d90832dc4