Move C++ code into cpp/ dir (#941)

- Moved C++ code to cpp/ from src/raspberrypi
- Related updates to Makefile, easyinstall.sh, and the github build rules
- Removed the native X68k C code in src/x68k from the repo

cpp/test/test_setup.cpp

@@ -0,0 +1,37 @@
+//---------------------------------------------------------------------------
+//
+// SCSI Target Emulator RaSCSI Reloaded
+// for Raspberry Pi
+//
+// Copyright (C) 2022 Uwe Seimet
+//
+//---------------------------------------------------------------------------
+
+#include <gtest/gtest.h>
+
+#include "spdlog/spdlog.h"
+
+// Also used by the RascsiExecutor tests
+bool enable_logging; //NOSONAR Must be global in order to be shared with the tests
+
+class Environment final : public ::testing::Environment
+{
+public:
+
+	Environment() = default;
+	~Environment() override = default;
+
+	void SetUp() override { spdlog::set_level(enable_logging ? spdlog::level::trace : spdlog::level::off); }
+};
+
+int main(int argc, char *[])
+{
+	// If any argument is provided the log level is set to trace
+	enable_logging = argc > 1;
+
+	testing::AddGlobalTestEnvironment(new Environment());
+
+	testing::InitGoogleTest();
+
+	return RUN_ALL_TESTS();
+}