Some URLs expect a User-Agent header.

Example (version 22.2.1.3767):
```sql
SELECT * FROM url('https://api.github.com/users/clickhouse','JSONAsString');
```
Results in:
```
Code: 86. DB::Exception: Received error from remote server /users/clickhouse. HTTP status code: 403 Forbidden, body: 
Request forbidden by administrative rules. Please make sure your request has a User-Agent header (http://developer.github.com/v3/#user-agent-required). Check https://developer.github.com for other possible causes.
: While executing URL. (RECEIVED_ERROR_FROM_REMOTE_IO_SERVER) (version 22.2.1.3767)
```

Maybe it's nice to always send a header along, something like `User-Agent: ClickHouse/22.2.1.3767` ?

if (read_range.end)
                    range_header_value = fmt::format("bytes={}-{}", getOffset(), *read_range.end);
                else
                    range_header_value = fmt::format("bytes={}-", getOffset());
                LOG_TEST(log, "Adding header: Range: {}", range_header_value);
                request.set("Range", range_header_value);
            }
            if (!credentials.getUsername().empty())
                credentials.authenticate(request);
            LOG_TRACE(log, "Sending request to {}", uri_.toString());
            auto sess = session->getSession();
            try
            {
                auto & stream_out = sess->sendRequest(request);
                if (out_stream_callback)
                    out_stream_callback(stream_out);
                istr = receiveResponse(*sess, request, response, true);
                response.getCookies(cookies);
                content_encoding = response.get("Content-Encoding", "");
                return istr;
            }
            catch (const Poco::Exception & e)
            {
                
                
                sess->attachSessionData(e.message());
                throw;
            }
        }
        std::optional<size_t> getTotalSize() override