mod_http_oauth2: Add Cache-Control and Pragma headers per by RFC 6749 These are mostly for the various Client-facing endpoints, so the chance of browsers being involved is slightly lower than with the User-facing authorization endpoint, which already sent the Cache-Control header. Thanks to OAuch for pointing out.

Prosody 0.12 added an API allowing modules to report their status. This
module allows reading these statuses via HTTP for use in monitoring.

```
$ curl http://prosody.localhost:5280/status
{
   "example.com" : {
      "c2s" : {
         "message" : "Loaded",
         "type" : "core"
      }
   }
}
```