mod_http_oauth2: Add support for the "openid" scope This "openid" scope is there to signal access to the userinfo endpoint, which is needed for OIDC support. We don't actually check this later because the userinfo endpoint only returns info embedded in the token itself, but in the future we may want to check this more carefully.

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"
      }
   }
}
```