Add Osiris settings to rabbitmq.conf

[acogoluegnes]

[michaelklishin]

Note that for Ra settings we use the raft prefix, not ra. So maybe here it would make sense to use streams or something similar, as osiris won't make much sense to most users.

[acogoluegnes]

Good point. We already use the stream prefix for the stream plugin (no s), this is the usual convention for plugins. I understand that streams makes more sense than osiris, but I'm afraid stream and streams could confuse people. What's your take on this?