[getMetrics] response format

[emilymcafee]

The final act of getMetrics will be to return all datapoints in a sensible way, that way they can be consumed for analysis later on.

@aarthykc I'm thinking the final response from getMetrics should be formatted like this:

{
    'request count': [ /* all of your datapoints here */ ],
    'latency': [ /* datapoints */ ],
    '2xx': [ /* datapoints */ ],
    '3xx': [ /* datapoints */ ],
    '4xx': [ /* datapoints */ ],
    '5xx': [ /* datapoints */ ]
}

Just opening this for visibility, you can implement in #1 and close here when done?

[aarthykc]

Dunzo ! in this - #1 PR.