Add a new controller to expose endpoints that can be used with shields.io

[devatherock]

The spec is documented at https://shields.io/endpoint. The embedded badge would look like https://img.shields.io/endpoint?url=... and the URL will be this to be created endpoint, which should return a response like below:

{
  "schemaVersion": 1,
  "label": "hello",
  "message": "sweet world",
  "color": "orange"
}

Exposing these endpoints would provide users a way to generate the badges directly from shields.io, taking advantage of its caching and also get around the occasional Received fatal alert: handshake_failure errors