doc: Populate the 'configuration' section

Per the spec [1]:

  configuration/ – automatically generated configuration reference
  information based on oslo.config’s sphinx integration (or manually
  written for projects not using oslo.config). Step-by-step guides for
  doing things like enabling cells or configuring a specific driver
  should be placed in the admin/ section.

Only the 'sample_policy' and 'sample_config' files fit into this
category at present. We may wish to add files that use the oslo.config
and oslo.policy Sphinx integrations, but that can come later.

[1] specs.openstack.org/openstack/docs-specs/specs/pike/os-manuals-migration

Change-Id: I587551ada1932876bca51a362f8dfeef6f7dd70b

doc/source/configuration/sample-config.rst

@@ -7,6 +7,7 @@ auto-generated from Nova when this documentation is built, so
 if you are having issues with an option, please compare your version of
 Nova with the version of this documentation.
 
-The sample configuration can also be viewed in `file form <_static/nova.conf.sample>`_.
+The sample configuration can also be viewed in :download:`file form
+</_static/nova.conf.sample>`.
 
-.. literalinclude:: _static/nova.conf.sample
+.. literalinclude:: /_static/nova.conf.sample

doc/source/configuration/sample-policy.rst

@@ -6,7 +6,7 @@ The following is a sample nova policy file, autogenerated from nova when this
 documentation is built. To prevent conflicts, ensure your version of nova
 aligns with the version of this documentation.
 
-The sample policy can also be viewed in `file form
-<_static/nova.policy.yaml.sample>`_.
+The sample policy can also be viewed in :download:`file form
+</_static/nova.policy.yaml.sample>`.
 
-.. literalinclude:: _static/nova.policy.yaml.sample
+.. literalinclude:: /_static/nova.policy.yaml.sample

doc/source/index.rst

@@ -199,7 +199,7 @@ Sample Configuration File
 .. toctree::
     :maxdepth: 1
 
-    sample_config
+    configuration/sample-config
 
 Sample Policy file
 ------------------
@@ -207,7 +207,7 @@ Sample Policy file
 .. toctree::
     :maxdepth: 1
 
-    sample_policy
+    configuration/sample-policy
 
 Man Pages
 ----------