feature(server): add /ver.json endpoint and route definition processing.

* Add automatic route processing for route declarations in the `server/lib/routes` subdirectory. A route declaration should contain three attributes, a method, path, and process.
* Steal @dcoates version code from fxa-auth-server and hook it up to /ver.json

/ver.json returns a JSON response that looks like:
```
{
    "version": "0.0.1",
    "commit": "ee3618cb8db106e51b246152fe1daf1f5336d208"
}
```

Closes #530