add configuration.rst file for oauth1

[Steve Martinelli]

I really like the way fabio added this file to the endpoint filtering extension, i'd like to add one for oauth1 as well.
example in endpoint filtering:
https://github.com/openstack/keystone/blob/9e8f89fa5342c3561979eecaad3e5a8dc63c4ee1/keystone/contrib/endpoint_filter/configuration.rst

[Dolph Mathews (dolph)]

If the rst was in doc/source/ instead of the python package, then it'd be published on:

  http://docs.openstack.org/developer/keystone/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/44463

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/44463
Committed: http://github.com/openstack/keystone/commit/a3a40563791d876f9b3568b3821ba019e305aba3
Submitter: Jenkins
Branch: master

commit a3a40563791d876f9b3568b3821ba019e305aba3
Author: Steve Martinelli <email address hidden>
Date: Fri Aug 30 09:54:39 2013 -0500

    Add a oauth1-configuration.rst and extension section to docs

    The patch addresses the following:
    1) Add an extensions section to the configuration.rst
    2) Add the oauth-configuration.rst to the previously mentioned
    section.

    fixes bug: #1218722

    Change-Id: I0c832d89698fc43a19408e8e7c159f09e0ec5e15