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/common/main.cpp b/common/main.cpp
new file mode 100644
index 0000000..732751f
--- /dev/null
+++ b/common/main.cpp
@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2019-2021, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include "CppUTest/CommandLineTestRunner.h"
+
+int main(int argc, char *argv[])
+{
+	return RUN_ALL_TESTS(argc, argv);
+}