Federated editing allows iframing remote servers by default in richdocuments

richdocuments is the repository for NextCloud Collabra, the app for Nextcloud Office collaboration. Prior to versions 6.0.0, 5.0.4, and 4.2.6, a user could be tricked into working against a remote Office by sending them a federated share. richdocuments versions 6.0.0, 5.0.4 and 4.2.6 contain a fix for this issue. There are currently no known workarounds available.