Docs: Restructuring and new layout

This patch implements a set of user-experiences aimed
changes.It modifies the documentation structure and
switches to a more reactive design for the rtd theme.

* The documentation layout has been redesigned to be more
  intuitive,easier to maintain and and scale.
* The landing page introduces a new dashboard.
* Introduced dedicated space for release documents, and
  changelog has been modified to directly source content
  from referenced documents.
* Added quick-link navigation for items that need emphasis.
* Relevant design documents can now be grouped in suf-folders.
* There is dedicated space for custom platform, and third
  party tools documents.
* Wildcard and regex matching has been introduced to indexes.

Change-Id: Ib02d17d5d26187d397ba17317788cf2a01401b07
Signed-off-by: Minos Galanakis <minos.galanakis@arm.com>
diff --git a/docs/conf.py.in b/docs/conf.py.in
index 81e1134..f3739be 100644
--- a/docs/conf.py.in
+++ b/docs/conf.py.in
@@ -125,7 +125,7 @@
 
 #Add custom css for HTML. Used to allow full page width rendering
 def setup(app):
-    app.add_stylesheet('css/custom.css')
+    app.add_stylesheet('css/tfm_custom.css')
 
 # -- Options for HTMLHelp output ---------------------------------------------