Add proper section/subsection to philosophy

Add overview, how not to do the job, how to do the job. :)

Change-Id: Id3c95ae376f92bfdeb9d43a2360bfd9f01e6f22f

doc/deployment-philosophy.rst

-Customize an OpenStack Deployment
-=================================
+Kolla's Philosophy on Deployment
+================================
 
-Kolla's Philosphy on Deployment
--------------------------------
+Overview
+--------
 
 Kolla has an objective to replace the inflexible, painful, resource intensive
 deployment process of OpenStack with a flexible, painless, inexpensive
@@ -19,6 +19,9 @@ operator's experience with OpenStack grows and the desire to customize
 OpenStack services increases, Kolla offers full capability to override every
 OpenStack service configuration option in the deployment.
 
+Why not Template Customization?
+-------------------------------
+
 The Kolla upstream community does not want to place key/value pairs in the
 Ansible playbook configuration options that are not essential to obtaining
 a functional deployment.  If the Kolla upstream starts down the path of