Murano docs: navigation restructure

Adds the Note to the top of the landing page informing the user
that the documentation is under development at the moment.
The link in this note leads to the new docs structure.

Change-Id: I7ba43658290e4ae2e2fe477fb58cbc6afccd4454

doc/source/draft/index.rst

@@ -3,9 +3,9 @@
 
 .. _content:
 
-===============================
-Welcome to Murano Documentation
-===============================
+======================================
+Welcome to Murano Documentation (BETA)
+======================================
 
 .. TODO add Abstract (OG)
 

doc/source/index.rst

@@ -17,8 +17,20 @@
 Welcome to Murano!
 ==================
 
+|
+
+.. note::
+   The latest version of this documentation is under development at the moment.
+   The most recently updated information is published as the :ref:`BETA version of
+   the Murano documentation <content>`.
+
+   We are restructuring and updating the information to make your user experience awesome,
+   and apologize for any inconvenience this may cause.
+
+|
+
 Introduction
-============
+~~~~~~~~~~~~
 
 Murano Project introduces an application catalog, which allows application
 developers and cloud administrators to publish various cloud-ready applications
@@ -46,11 +58,9 @@ Murano consists of several source code repositories:
 .. _murano-dashboard: https://git.openstack.org/cgit/openstack/murano-dashboard/
 .. _python-muranoclient: https://git.openstack.org/cgit/openstack/python-muranoclient/
 
-
 This documentation offers information on how Murano works and how to
 contribute to the project.
 
-
 Developing Applications
 ~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -129,16 +139,9 @@ Developing Applications
 
 
 Indices and tables
-==================
+~~~~~~~~~~~~~~~~~~
 
 * :ref:`genindex`
 * :ref:`modindex`
 * :ref:`search`
 
-BETA: Murano documentation
-==========================
-
-.. toctree::
-   :maxdepth: 1
-
-   draft/index