OLDIsim should report Peak QPS and the average+variance of each nodes QPS

Today OLDIsim reports out the scaling efficiency only as seen here https://github.com/GoogleCloudPlatform/PerfKitBenchmarker/blob/master/perfkitbenchmarker/benchmarks/oldisim_benchmark.py#L237

It would also be useful to know the peak QPS and latency of the best node, worst node, and average+std of all nodes.

Here is example output data;
peak qps = 312, latency = 51.4
requested_qps = 156, measured_qps = 155, latency = 6.8
requested_qps = 234, measured_qps = 230, latency = 8.1
requested_qps = 273, measured_qps = 267, latency = 13.5
requested_qps = 292, measured_qps = 287, latency = 24.4
requested_qps = 302, measured_qps = 288, latency = 22.9
requested_qps = 307, measured_qps = 291, latency = 25.9