Docs: Clean and restructure the Integration guide

Signed-off-by: Anton Komlev <anton.komlev@arm.com>
Change-Id: I8dca6e3d5cf5cae3a5cd3dc8f2b1e518ab3c20cf
diff --git a/docs/index.rst b/docs/index.rst
index c606c79..8fc23ff 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -1,5 +1,6 @@
+################################
 Trusted Firmware-M Documentation
-================================
+################################
 
 .. raw:: html
 
@@ -68,6 +69,7 @@
 
 .. toctree::
     :caption: Overview
+    :titlesonly:
     :maxdepth: 1
     :hidden:
 
@@ -79,6 +81,7 @@
 
 .. toctree::
     :caption: Development
+    :titlesonly:
     :maxdepth: 1
     :hidden: