Split metrics from `device` resource

[fisehara]

Remodel device resource and split metrics into device metrics record

This reduces the load on the device resource when updating device metrics periodically. device metrics are far less frequently needed than the device resource. Thus writing to the heavily used device resource should be offloaded to the device metrics record resource.

Change-type: major

[fisehara]

@Page- @thgreasi when this is fine I'll follow up with a PR for finalising the async migration and dropping the columns from device resource.