chore: move json classes to json folder

src/ObjCommon/Utils/JsonOptional.h

@@ -1,37 +0,0 @@
-#pragma once
-
-#include <nlohmann/json.hpp>
-#include <optional>
-
-// partial specialization (full specialization works too)
-namespace nlohmann
-{
-    template<typename T> struct adl_serializer<std::optional<T>>
-    {
-        static void to_json(json& j, const std::optional<T>& opt)
-        {
-            if (!opt.has_value())
-            {
-                j = nullptr;
-            }
-            else
-            {
-                j = *opt; // this will call adl_serializer<T>::to_json which will
-                          // find the free function to_json in T's namespace!
-            }
-        }
-
-        static void from_json(const json& j, std::optional<T>& opt)
-        {
-            if (j.is_null())
-            {
-                opt = std::nullopt;
-            }
-            else
-            {
-                opt = j.template get<T>(); // same as above, but with
-                                           // adl_serializer<T>::from_json
-            }
-        }
-    };
-} // namespace nlohmann