device/interface: add "tags" attribute from config to status dump

device/interface: add "tags" attribute from config to status dump

This allows annotating interfaces/devices in the config in a way that can be
queried through status. One example use case is to mark wifi interfaces for
use with specific services without having to explicitly reference sections
from elsewhere.

Signed-off-by: Felix Fietkau <nbd@nbd.name>