New plugin: Elastic APM integration

[TimoGoebel]

@lzap

I will add to that Foreman can export similar telemetry data itself to any monitoring system which handles Prometheus or Statsd protocols. This is complementary to the Elastic APM integration in case you don’t use ELK stack.

Nice. The ruby elastic agent currently does not export the backtrace where the sql statement has occurred. This would be super useful to have as well.