Move developer documentation to its own subtree

Prior to this change, all files at the root of the doc/source/ directory
were implied to be developer documentation. This commit moves them into
an explicit subdirectory, and re-words the section headings to be less
repetitive.

No changes to formatting or content were introduced.

Change-Id: Id00116ad2146f11df52dd8a331834719e1b8bd03
Closes-Bug: #1486789

doc/source/developer-docs/index.rst

@@ -0,0 +1,23 @@
+Developer Documentation
+=======================
+
+In this section, you will find documentation relevant to developing
+os-ansible-deployment.
+
+Contents:
+
+.. toctree::
+   :maxdepth: 2
+
+   playbooks
+   extending
+   scripts
+
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`
+

doc/source/developer-docs/playbooks.rst

@@ -1,5 +1,5 @@
-os-ansible-deployment Playbooks
+Playbooks
-===============================
+=========
 
 The OpenStack Ansible playbooks are stored in the playbooks directory.
 

doc/source/developer-docs/scripts.rst

@@ -1,5 +1,5 @@
-OpenStack Ansible Deployment Scripts
+Included Scripts
-====================================
+================
 
 The repository contains several helper scripts to manage gate jobs,
 install base requirements, and update repository information. Invoke

doc/source/index.rst

@@ -17,10 +17,8 @@ Contents:
 .. toctree::
    :maxdepth: 2
 
-   playbooks
    install-guide/index
-   extending
+   developer-docs/index
-   scripts
 
 
 Indices and tables