DOC: update documentation.

Add documentation covering:
  - developer information about architecture
  - project structure and building
  - project overview and service descriptions
  - the portability model for supporting hardware

Signed-off-by: Julian Hall <julian.hall@arm.com>
Co-Authored-By: Gyorgy Szing <gyorgy.szing@gmail.com>
Change-Id: I8bf9c01a66350719d82a7ca2bc1c78a8ab17978d
diff --git a/docs/developer/deployments.rst b/docs/developer/deployments.rst
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+Deployments
+===========
+In the context of the Trusted Services project, a deployment represents a unit of functionality
+that is built for a specific environment.  You can find out more about deployments here
+:ref:`Project Structure`.
+
+The following table lists currently supported deployments:
+
+.. list-table:: Supported deployments
+  :header-rows: 1
+
+  * - Deployment Name
+    - Environments
+    - Provides
+    - Used for
+  * - component-test
+    - linux-pc, arm-linux
+    - Standalone tests for components and integrations
+    - Test driven development and regression testing
+  * - ts-service-test
+    - linux-pc, arm-linux
+    - Service API level tests
+    - Tests services from perspective of client application
+  * - ts-demo
+    - linux-pc, arm-linux
+    - Demonstration client application
+    - Example user-space client application
+  * - libts
+    - linux-pc, arm-linux
+    - Provides standard client interface for locating services and establishing RPC sessions
+    - Client application development
+  * - crypto
+    - opteesp
+    - Crypto trusted service
+    - Production deployments
+  * - secure-storage
+    - opteesp
+    - Secure storage trusted service
+    - Production deployments
+  * - libsp
+    - opteesp
+    - FF-A interface library
+    - FF-A library used in secure partition environments
+
+--------------
+
+*Copyright (c) 2020-2021, Arm Limited and Contributors. All rights reserved.*
+
+SPDX-License-Identifier: BSD-3-Clause