tf_fuzz: refactor includes to only include what is needed

* Refactor Makefile to automatically gather prerequisites.

* Change the includes (using include-what-you-need) so that files only
  include the specific headers they need. Many includes are also now
  inside the .hpp files instead of the .cpp files.

  This improves editor support: previously, external symbols in .hpp
  files would not be resolved by clangd due to .hpp files not having any
  imports.

Change-Id: Iece03f81c35aa43ac026aaeb49b87d2c4acf07cd
Signed-off-by: Nik Dewally <Nik.Dewally@arm.com>
diff --git a/tf_fuzz/tfz-cpp/utility/variables.cpp b/tf_fuzz/tfz-cpp/utility/variables.cpp
index ab2a823..7209074 100644
--- a/tf_fuzz/tfz-cpp/utility/variables.cpp
+++ b/tf_fuzz/tfz-cpp/utility/variables.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Arm Limited. All rights reserved.
+ * Copyright (c) 2024, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
@@ -8,28 +8,13 @@
 /* This file defines information to track regarding variables in the generated test
    code. */
 
+#include <stdlib.h>
 #include <string>
-#include <vector>
-#include <list>
-#include <iostream>
-#include <fstream>
 
-#include "class_forwards.hpp"
-
-#include "data_blocks.hpp"
-#include "psa_asset.hpp"
-#include "crypto_asset.hpp"
-#include "psa_call.hpp"
 #include "find_or_create_asset.hpp"
 #include "variables.hpp"
 #include "gibberish.hpp"
 
-/* This project's header files #including other project headers quickly becomes
-   unrealistically complicated.  The only solution is for each .cpp to include
-   the headers it needs.  However these in particular are mostly axiomatic:  Not
-   dependent upon other classes. */
-
-
 using namespace std;