Allow to replicate change request events

Change requests are standard page that could be replicated with the replication extension.
However, the specific change requests notifications are not systematically replicated by the extension, so we need to implement this replication, to ensure that change requests are properly displayed in all replicated instances.

To do so, we can use the following: https://extensions.xwiki.org/xwiki/bin/view/Extension/Replication%20Application/#HImplementanewtypeofreplication and ensure to not send a message when the change request is not replicated.