Visualize benchmark results

[loganek]

Benchmarks generate nice JSON output; we could setup some service (e.g. elasticsearch) where we we upload the file, it's automatically processed and add records to the database, which then is queried to visualize performance results. We could use this results as a check for new pull requests as well.

Example benchmark output below:

{
  "context": {
    "date": "2018-05-09 22:47:59",
    "num_cpus": 4,
    "mhz_per_cpu": 3300,
    "cpu_scaling_enabled": true,
    "library_build_type": "debug"
  },
  "benchmarks": [
    {
      "name": "BenchmarkTimelineInitEvent",
      "iterations": 13621478,
      "real_time": 4.6952823473601420e+01,
      "cpu_time": 4.6881388495433463e+01,
      "time_unit": "ns"
    },
    {
      "name": "BenchmarkTimelinePushBaseEventNoListener/1024",
      "iterations": 38253731,
      "real_time": 1.8052485233748008e+01,
      "cpu_time": 1.8031429927710846e+01,
      "time_unit": "ns"
    }
  ]
}