Codechange: vendor the nlohmann-json library (#11290)

(cherry picked from commit ba67f39db6)

# Conflicts:
#	.github/workflows/ci-build.yml
#	CMakeLists.txt
#	COMPILING.md
#	src/os/macosx/survey_osx.cpp
#	src/os/windows/survey_win.cpp
#	src/script/api/script_admin.cpp
#	src/script/api/script_event_types.cpp
#	src/tests/test_script_admin.cpp

src/os/macosx/survey_osx.cpp

@@ -10,10 +10,10 @@
 #include "../../stdafx.h"
 
 #include "../../core/format.hpp"
+#include "../../3rdparty/nlohmann/json.hpp"
 #include "macos.h"
 
 #include <mach-o/arch.h>
-#include <nlohmann/json.hpp>
 #include <thread>
 
 #include "../../safeguards.h"

src/os/unix/survey_unix.cpp

@@ -9,7 +9,8 @@
 
 #include "../../stdafx.h"
 
-#include <nlohmann/json.hpp>
+#include "../../3rdparty/nlohmann/json.hpp"
+
 #include <sys/utsname.h>
 #include <thread>
 #include <unistd.h>

src/os/windows/survey_win.cpp

@@ -10,8 +10,8 @@
 #include "../../stdafx.h"
 
 #include "../../core/format.hpp"
+#include "../../3rdparty/nlohmann/json.hpp"
 
-#include <nlohmann/json.hpp>
 #include <thread>
 #include <windows.h>