Adapt watcher documentation for new standards

This patch set makes the following changes:

 * Add index file to each subdirectory of doc/source
 * Update doc/source/index.rst with new links
 * Move content of install-guide to the doc/source/install
 * Minor changes

Depends-On: Ifc5512c0e2373cf3387e0e0498268eab092e52bb
Change-Id: Iecb4f60efb015a56b9b37331859848b287112842

doc/source/install/get_started.rst

@@ -0,0 +1,27 @@
+============================================
+Infrastructure Optimization service overview
+============================================
+The Infrastructure Optimization service provides flexible and scalable
+optimization service for multi-tenant OpenStack based clouds.
+
+The Infrastructure Optimization service consists of the following components:
+
+``watcher`` command-line client
+  A CLI to communicate with ``watcher-api`` to optimize the cloud.
+
+``watcher-api`` service
+  An OpenStack-native REST API that accepts and responds to end-user calls
+  by processing them and forwarding to appropriate underlying watcher
+  services via AMQP.
+
+``watcher-decision-engine`` service
+  It runs audit and return an action plan to achieve optimization goal
+  specified by the end-user in audit.
+
+``watcher-applier`` service
+  It executes action plan built by watcher-decision-engine. It interacts with
+  other OpenStack components like nova to execute the given action
+  plan.
+
+``watcher-dashboard``
+  Watcher UI implemented as a plugin for the OpenStack Dashboard.