Added a new statistic for per-user query response bytes

[davidby-influx]

ETA: 1.12.3, estimated by end of February
PR: feat: report user query bytes

• Admins can now see how many bytes each user has queried.
• /debug/vars, SHOW STATS, _internal all have this information

Relevant URLs

FR: Index Exchange: Display read rates from user initiated queries

1. InfluxDB OSS 1.12.3
2. InfluxDB Enterprise 1.12.3