[XAM] Improvements to XamUserReadProfileSettingsEx/
XamUserWriteProfileSettings.
- Unify X_USER_READ_PROFILE_SETTING and X_USER_WRITE_PROFILE_SETTING
into X_USER_PROFILE_SETTING.
- Clean up Setting serialization to use X_USER_PROFILE_SETTING_DATA
instead of manual buffer copying.
- Fix XamUserReadProfileSettingsEx case where user_index is non-zero
and xuids are being used.
- Skip unset settings in XamUserWriteProfileSettings_entry.
C++17ification!
- Filesystem interaction now uses std::filesystem::path.
- Usage of const char*, std::string have been changed to
std::string_view where appropriate.
- Usage of printf-style functions changed to use fmt.
