Add initial version of firmware-test-builder

Introduce the following features to firmware-test-builder:

* Testing on the host machine (PC)
* Provides CMake functions for building/running/evaluating tests
  * Checking prerequisites (git, c-picker, libclang, etc.)
  * Fetching and building CppUTest
  * Defining and building unit test suites (i.e. separate binaries)
  * Handling c-picker based extraction of code snippets
  * Registering test suites to CTest (CMake's test system) which runs
    all the test binaries
* Generating coverage report
* Documentation of the system

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: Ic0a1af55bef07c6e76071193caa94a9a48f9041f
diff --git a/docs/components/c_picker.rst b/docs/components/c_picker.rst
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+c-picker
+========
+
+c-picker uses ``libclang``'s Python interface for parsing source files.
+
+Command line options
+--------------------
+
+- ``-h, --help`` - Showing help message
+- ``--root ROOT`` - Root source directory
+- ``--config CONFIG`` - Configuration file (``.json|.yml``)
+- ``--output OUTPUT`` - Output file
+- ``--print-dependencies`` - Prints the dependencies
+- ``--version`` - Shows the program's version number and exit
+- ``--args ...``  - clang arguments
+
+
+Configuration file format
+-------------------------
+
+c-picker configuration can be described in ``JSON`` or ``YAML`` format using the same object structure.
+
+- ``elements`` - List of elements to pick from the original code
+
+  - ``name`` - Name of the element
+  - ``type`` - Type of the element: ``include``, ``function``, ``variable``
+  - ``args`` - Arguments for clang used during picking the element
+  - ``options`` - Currenly the only options is ``remove_static`` which removes
+    the ``static`` qualifier from the element's definition.
+
+- ``options`` - Global options for all elements
+- ``args`` - Global clang arguments for all elements
+
+YAML example
+------------
+
+YAML format is preferred because it can contain metadata like comments and licence information.
+
+.. code-block:: YAML
+
+  elements:
+  - file: bl1/bl1_fwu.c
+    type: variable
+    name: bl1_fwu_loaded_ids
+    options: [remove_static]
+  - file: bl1/bl1_fwu.c
+    type: function
+    name: bl1_fwu_add_loaded_id
+    options: [remove_static]
+  - file: bl1/bl1_fwu.c
+    type: function
+    name: bl1_fwu_remove_loaded_id
+    options: [remove_static]
+  args:
+  - -DFWU_MAX_SIMULTANEOUS_IMAGES=10
+  - -DINVALID_IMAGE_ID=0xffffffff
+
+
+--------------
+
+*Copyright (c) 2019-2021, Arm Limited. All rights reserved.*