enhancement: Remove `json.hpp` (3rd party dependency)

[pooranjoyb]

The current version uses json.hpp to handle API payloads efficiently with JSON data. Check nholmann/json for reference.

But as this is a 3rd party dependency, we need to make changes in the APIs (that uses nholmann/json) so that we can replace json.hpp header completely from our SDK. This dependency was initially used to fasten the development, but as we move forward with future versions, we can improve the SDK by removing external dependency and creating the payloads from scratch.

Example :

cpp-sdk-appwrite/src/services/Databases.cpp

Lines 765 to 771 in 215de2e

	json payloadJson = {
	{"databaseId", databaseId},
	{"collectionId", collectionId},
	{"key", key},
	{"type", type},
	{"attributes", attributes}
	};

This has to be removed and updated to something like this

    std::string attributesStr = "[";
    for(auto attribute : attributes) {
        attributesStr += "\"" + attribute + "\",";
    }
    attributesStr.pop_back();
    attributesStr += "]";
    std::string payload = R"({"databaseId":")" + databaseId 
                            + R"(","collectionId":")" + collectionId 
                            + R"(","key":")" + key 
                            + R"(","type":")" + type 
                            + R"(","attributes":)" + attributesStr + R"(})";

[SharonIV0x86]

I believe this can be replaced with std::format but it requires C++ 20.

[pooranjoyb]

I believe this can be replaced with std::format but it requires C++ 20.

Yes, I know we're quite naive to start with C++11 in 2024, but we'll reconsider this soon once we have a stable version with 95% API coverage. Would really appreciate your contributions. We're using raw strings as of now :))