since some games don't call `SteamAPI_RunCallbacks()` or `SteamAPI_ManualDispatch_RunFrame()` or `Steam_BGetCallback()`
hence all run_callbacks() will never run, also networking callbacks won't run
* edits by Kola124 + other changes in the settings parser
* random ugc mod handle at object creation
* file size using std::filesystem + fix warnings + some print + arg validation