**Describe the solution you'd like**

An option to make the `IDENTIFIED WITH` section mandatory.

#include <mutex>
namespace DB
{
namespace ErrorCodes
{
    extern const int UNKNOWN_ELEMENT_IN_CONFIG;
    extern const int UNKNOWN_SETTING;
    extern const int AUTHENTICATION_FAILED;
}
namespace
{
    void checkForUsersNotInMainConfig(
        const Poco::Util::AbstractConfiguration & config,
        const std::string & config_path,
        const std::string & users_config_path,
        Poco::Logger * log)
    {
        if (config.getBool("skip_check_for_incorrect_settings", false))
            return;
        if (config.has("users") || config.has("profiles") || config.has("quotas"))
        {
            
            
            LOG_ERROR(log, "The <users>, <profiles> and <quotas> elements should be located in users config file: {} not in main config {}."
                " Also note that you should place configuration changes to the appropriate *.d directory like 'users.d'.",
                users_config_path, config_path);
        }
    }
}
class AccessControl::ContextAccessCache