**Use case**
ClickHouse as a web server becomes a viable scenario.
(At least in backoffice).

**Describe the solution you'd like**
Add this field.

**Additional context**
It's in question how to name it. The original HTTP specs has the famous typo in it and name it `referer`. While JavaScript has this typo fixed and name it `referrer`.

for (const UInt64 thread_id : process.thread_ids)
                threads_array.emplace_back(thread_id);
            res_columns[i++]->insert(threads_array);
        }
        {
            IColumn * column_profile_events_names = res_columns[i++].get();
            IColumn * column_profile_events_values = res_columns[i++].get();
            if (process.profile_counters)
                ProfileEvents::dumpToArrayColumns(*process.profile_counters, column_profile_events_names, column_profile_events_values, true);
            else
            {
                column_profile_events_names->insertDefault();
                column_profile_events_values->insertDefault();
            }
        }
        {
            IColumn * column_settings_names = res_columns[i++].get();
            IColumn * column_settings_values = res_columns[i++].get();
            if (process.query_settings)
                process.query_settings->dumpToArrayColumns(column_settings_names, column_settings_values, true);
            else
            {
                column_settings_names->insertDefault();
                column_settings_values->insertDefault();
            }
        }
    }
}
}