Removing redundant dependencies. User story: As a **developer**, I want to **remove redundant dependency installation**, so that **to ensure a cleaner project dependency graph**. DoD: - [x] Remove dependency `jsoncpp` from `conanfile.py` Technical details: - [`jsoncpp`](https://conan.io/center/recipes/jsoncpp?version=1.9.6) is [a dependency of `Drogon`](https://conan.io/center/recipes/drogon), so explicit installation of this package is not required.