mod_http_oauth2: Reflect ALL attributes of the client registration Per RFC 7591: " Additionally, the authorization server MUST return all registered metadata about this client, including any fields provisioned by the authorization server itself. " The idea is that the server may replace/drop fields in the registration, so what gets reflected back to the client is the source of truth about the registration.

Over the years, some servers stop working for various reasons, and leave
behind broken roster subscriptions that trigger failing s2s connections.
This module allows cleaning up such cases by unsubscribing local users
from their contacts on those servers. Also works for typos and the like.
Use with care.

```lua
Component "gmail.com" "unsubscriber"
```