Docs: Clean and restructure the Integration guide

Signed-off-by: Anton Komlev <anton.komlev@arm.com>
Change-Id: I8dca6e3d5cf5cae3a5cd3dc8f2b1e518ab3c20cf
diff --git a/docs/conf.py b/docs/conf.py
index 701419e..425f1a6 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -97,7 +97,7 @@
     'prev_next_buttons_location' : None,   # Hide Prev and Next buttons
     'display_version': True,    # Show version under logo
     'sticky_navigation': True,
-    'navigation_depth': 2,
+    'navigation_depth': 3,
 }
 
 # Remove the "View page source" link from the top of docs pages