Draft: Set wayland_output name to "model serialnumber" rather than ConnectorName
This will make output names and uuid constant per-ouput.
Connector Name are, id in particulary, volatile.
This will allow plasmashell to restore containment settings regardless of the connector a screen is connected to.
This will imply settings loss for users though, old containments will be lost with this. This is more to open a discussion first.
WaylandOutputDevice already uses "Vendor model serialnumber" used by Kscreen.