Manufacturer is required for Devices

[squaregoldfish]

In the metadata editor for Devices, model seems to be required (if that's what a yellow heading on a property indicates), but manufacturer is not. I've added the manufacturer as a limit, which I believe will make it required. I've also restricted it to Commercial Companies, as is done elsewhere in the spec.

[mirzov]

To make it required, one needs to add a cardinality restriction (e.g. someValuesFrom)