**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`.

: server(server_)
    , log(&Poco::Logger::get(name))
{
    server_display_name = server.config().getString("display_name", getFQDNOrHostName());
}
void HTTPHandler::processQuery(
    Context & context,
    Poco::Net::HTTPServerRequest & request,
    HTMLForm & params,
    Poco::Net::HTTPServerResponse & response,
    Output & used_output,
    std::optional<CurrentThread::QueryScope> & query_scope)
{
    LOG_TRACE(log, "Request URI: {}", request.getURI());
    std::istream & istr = request.stream();
    
    
    std::string user = request.get("X-ClickHouse-User", "");