Add cli/ directory for documentation

The specification detailing the great documentation migration
requires a doc/source/cli/ directory be added to the project.
The directory is intended for cli documentation.

This commit add the directory so that we are in compliance with the
specification but doesn't move any content into the directory. It is
instead treated like a placeholder until we can migrate the right
content into the cli guide.

Change-Id: Ida5ffc979d3c596547e9664dce8933d2cf9a4486
Closes-Bug: 1694460

doc/source/cli/index.rst

@@ -0,0 +1,23 @@
+..
+      Copyright 2017 OpenStack Foundation
+      All Rights Reserved.
+
+      Licensed under the Apache License, Version 2.0 (the "License"); you may
+      not use this file except in compliance with the License. You may obtain
+      a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+      Unless required by applicable law or agreed to in writing, software
+      distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+      WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+      License for the specific language governing permissions and limitations
+      under the License.
+
+=================
+CLI Documentation
+=================
+
+This section will eventually consist of documentation migrated from other
+guides. This is a placeholder until content best suited for this guide is
+migrated.

doc/source/index.rst

@@ -98,6 +98,16 @@ This section contains the documentation for end-users of keystone.
 
     user/index.rst
 
+CLI Documentation
+~~~~~~~~~~~~~~~~~
+
+This section details information related to ``keystone-manage``.
+
+.. toctree::
+    :maxdepth: 2
+
+    cli/index.rst
+
 Administrator Guides
 ~~~~~~~~~~~~~~~~~~~~