Deduplicate config/policy reference docs from main index

The top level index (home page) was duplicating the
configuration/index content, so this simply changes
the home page into a table of contents for the configuration
sub-tree and leaves the config/policy content in the
sub-tree. This will be needed when we add docs about
placement policy.

The hidden configuration toc tree items are moved
into the sub-tree configuration/index to be closer
to the actual documents we're hiding from the toc tree.

Related to blueprint granular-placement-policy

Change-Id: Iad87dc339278ee7e7cf8de5eea252bbb7a5f75c2

doc/source/configuration/index.rst

@@ -14,10 +14,10 @@ Configuration
   configuration guides for various parts of you Nova system. Helpful reference
   for setting up specific hypervisor backends.
 
-* :doc:`Config Reference </configuration/config>`: A complete reference of all
+* :doc:`Config Reference <config>`: A complete reference of all
   configuration options available in the ``nova.conf`` file.
 
-* :doc:`Sample Config File </configuration/sample-config>`: A sample config
+* :doc:`Sample Config File <sample-config>`: A sample config
   file with inline documentation.
 
 Policy
@@ -26,8 +26,20 @@ Policy
 Nova, like most OpenStack projects, uses a policy language to restrict
 permissions on REST API actions.
 
-* :doc:`Policy Reference </configuration/policy>`: A complete reference of all
+* :doc:`Policy Reference <policy>`: A complete reference of all
   policy points in nova and what they impact.
 
-* :doc:`Sample Policy File </configuration/sample-policy>`: A sample policy
+* :doc:`Sample Policy File <sample-policy>`: A sample policy
   file with inline documentation.
+
+
+.. # NOTE(mriedem): This is the section where we hide things that we don't
+   # actually want in the table of contents but sphinx build would fail if
+   # they aren't in the toctree somewhere.
+.. toctree::
+   :hidden:
+
+   config
+   sample-config
+   policy
+   sample-policy

doc/source/index.rst

@@ -180,27 +180,8 @@ Reference Material
 
 * :doc:`Nova CLI Command References </cli/index>`: the complete command reference
   for all the daemons and admin tools that come with nova.
-
+* :doc:`Configuration Guide <configuration/index>`: Information on configuring
-* **Configuration**:
+  the system, including role-based access control policy rules.
-
-  * :doc:`Configuration Guide </admin/configuration/index>`: detailed
-    configuration guides for various parts of you Nova system. Helpful
-    reference for setting up specific hypervisor backends.
-
-  * :doc:`Config Reference </configuration/config>`: a complete reference of all
-    configuration options available in the nova.conf file.
-
-  * :doc:`Sample Config File </configuration/sample-config>`: a sample config file
-    with inline documentation.
-
-* **Policy**: nova, like most OpenStack projects, uses a policy language to
-  restrict permissions on REST API actions.
-
-  * :doc:`Policy Reference </configuration/policy>`: a complete reference of all
-    policy points in nova and what they impact.
-
-  * :doc:`Sample Policy File </configuration/sample-policy>`: a sample policy file
-    with inline documentation.
 
 For Contributors
 ================
@@ -233,10 +214,6 @@ looking parts of our architecture. These are collected below.
    admin/configuration/index
    cli/index
    configuration/index
-   configuration/config
-   configuration/sample-config
-   configuration/policy
-   configuration/sample-policy
    contributor/development-environment
    contributor/api
    contributor/api-2