mod_groups_internal: allow force-emitting group member addition events This is useful when a new plugin was loaded which handles that event to add some value. Then the command can be called (**not** from the plugin but from an upcoming admin shell module) to synchronise things.

This module helps make BOSH and WebSocket connection endpoints
discoverable via the HTTP method described in
[XEP-0156](https://xmpp.org/extensions/xep-0156.html#http).