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/Makefile b/docs/Makefile
new file mode 100644
index 0000000..04e3a70
--- /dev/null
+++ b/docs/Makefile
@@ -0,0 +1,25 @@
+#
+# Copyright (c) 2019-2021, Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+# Minimal makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line, and also
+# from the environment for the first two.
+SPHINXOPTS    ?=
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = .
+BUILDDIR      = _build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)