Add extension points to MUC

Description

https://github.com/igniterealtime/Openfire/pull/669

This PR adds extension points to MUC, allowing both Services and Rooms to be extended by plugins (and other code).

Environment

None
Fixed

Assignee

Dave Cridland

Reporter

Daryl Herzmann

Labels

None

Expected Effort

None

Ignite Forum URL

None

Components

Fix versions

Affects versions

Priority

Major
Configure