This makes it easier to spot syntax errors when editing the
class reference. The schema is referenced locally so validation
can still work offline.
Each class XML's schema conformance is also checked on GitHub Actions.
The default autoplace algorithm places instances in the highest priority Room. It became apparent that there are some situations in which users will want to override this and force placement in a Room from a particular RoomGroup, especially an "outside" RoomGroup.
This setting allows the user to specify a preference for Room priority. When set to 0, the setting is ignored and the highest priority Room is chosen.
