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/platform/ext/index.rst b/platform/ext/index.rst
new file mode 100644
index 0000000..e0d87f3
--- /dev/null
+++ b/platform/ext/index.rst
@@ -0,0 +1,42 @@
+Platforms
+=========
+
+.. toctree::
+    :maxdepth: 1
+    :caption: Information
+
+    readme
+    /platform/readme
+
+.. toctree::
+    :maxdepth: 4
+    :caption: arm
+    :glob:
+
+    target/musca_*/**
+    otp_provisioning.rst
+
+.. toctree::
+    :maxdepth: 4
+    :caption: NXP
+    :glob:
+
+    target/nxp/**
+
+.. toctree::
+    :maxdepth: 4
+    :caption: Cypress
+    :glob:
+
+    target/cypress/**
+
+.. toctree::
+    :maxdepth: 4
+    :caption: STM
+    :glob:
+
+    target/stm/**
+
+--------------
+
+*Copyright (c) 2020, Arm Limited. All rights reserved.*
diff --git a/platform/ext/target/cypress/psoc64/cypress_psoc64_spec.rst b/platform/ext/target/cypress/psoc64/cypress_psoc64_spec.rst
index e6b5d84..eca6594 100644
--- a/platform/ext/target/cypress/psoc64/cypress_psoc64_spec.rst
+++ b/platform/ext/target/cypress/psoc64/cypress_psoc64_spec.rst
@@ -13,10 +13,10 @@
 policy_multi_img_CM0p_CM4_debug_2M.json
 
 Please make sure you have all required software installed as explained in the
-:doc:`software requirements </docs/user_guides/tfm_sw_requirement>`.
+:doc:`software requirements </docs/getting_started/tfm_sw_requirement>`.
 
 Please also make sure that all the source code are fetched by following
-:doc:`general building instruction </docs/user_guides/tfm_build_instruction>`.
+:doc:`general building instruction </docs/getting_started/tfm_build_instruction>`.
 
 Install CySecureTools.
 
diff --git a/platform/ext/target/nxp/lpcxpresso55s69/README.rst b/platform/ext/target/nxp/lpcxpresso55s69/README.rst
index 451a9e3..a9b8929 100644
--- a/platform/ext/target/nxp/lpcxpresso55s69/README.rst
+++ b/platform/ext/target/nxp/lpcxpresso55s69/README.rst
@@ -146,7 +146,7 @@
 
     **NOTE**: When debugging with the mbed-crypto library, you also require an
     additional ``-DMBEDCRYPTO_DEBUG=ON`` compile-time switch, as defined here:
-    :ref:`docs/user_guides/tfm_build_instruction:Configuring the build`
+    :ref:`docs/getting_started/tfm_build_instruction:Configuring the build`
 
 
 Start the GDB server, pointing to the secure application image: