**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`.

res_columns[i++]->insert(process.client_info.current_address.port());
        res_columns[i++]->insert(process.client_info.initial_user);
        res_columns[i++]->insert(process.client_info.initial_query_id);
        res_columns[i++]->insertData(IPv6ToBinary(process.client_info.initial_address.host()).data(), 16);
        res_columns[i++]->insert(process.client_info.initial_address.port());
        res_columns[i++]->insert(UInt64(process.client_info.interface));
        res_columns[i++]->insert(process.client_info.os_user);
        res_columns[i++]->insert(process.client_info.client_hostname);
        res_columns[i++]->insert(process.client_info.client_name);
        res_columns[i++]->insert(process.client_info.client_tcp_protocol_version);
        res_columns[i++]->insert(process.client_info.client_version_major);
        res_columns[i++]->insert(process.client_info.client_version_minor);
        res_columns[i++]->insert(process.client_info.client_version_patch);
        res_columns[i++]->insert(UInt64(process.client_info.http_method));
        res_columns[i++]->insert(process.client_info.http_user_agent);
        res_columns[i++]->insert(process.client_info.forwarded_for);
        res_columns[i++]->insert(process.client_info.quota_key);
        res_columns[i++]->insert(process.elapsed_seconds);
        res_columns[i++]->insert(process.is_cancelled);
        res_columns[i++]->insert(process.read_rows);
        res_columns[i++]->insert(process.read_bytes);
        res_columns[i++]->insert(process.total_rows);
        res_columns[i++]->insert(process.written_rows);
        res_columns[i++]->insert(process.written_bytes);
        res_columns[i++]->insert(process.memory_usage);
        res_columns[i++]->insert(process.peak_memory_usage);
        res_columns[i++]->insert(process.query);
        {
            Array threads_array;
            threads_array.reserve(process.thread_ids.size());