Expose the needsdiagnosis data to webcompat-metrics-client

[karlcow]

in #3 we agreed on a format.
For not blocking @magsout in anyway on his work, I will put the data in the right format on la-grange.net and then we can adjust later the domain name.

[karlcow]

@magsout this is for you ❤️

→ http HEAD http://www.la-grange.net/tmp/needsdiagnosis-timeline

HTTP/1.1 200 OK
Accept-Ranges: bytes
Connection: Keep-Alive
Content-Length: 6410
Content-Location: needsdiagnosis-timeline.json
Content-Type: application/json
Date: Thu, 26 Apr 2018 04:49:29 GMT
ETag: "190a-56ab918f8b600;56ab90b062780"
Expires: Thu, 03 May 2018 04:49:29 GMT
Keep-Alive: timeout=5, max=100
Last-Modified: Thu, 26 Apr 2018 04:48:24 GMT
Server: Apache/2.4.29 (FreeBSD)
TCN: choice
Vary: negotiate

The domain name will change in the future, but not the format. And it gives you something to work with.

Note that I will switch from daily to hourly in a near future. This is a static version for now.

[magsout]

cool thanks @karlcow

good job.

[karlcow]

This was last week and it is now obsolete with #10