[PATCH netifd] interface: support "zone" config option

[Felix Fietkau]

On 27.07.22 07:34, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal at milecki.pl>
> 
> Many protocol handlers support "zone" option independently and they pass
> it in the "data". Then it's read e.g. by a firewall[34].
> 
> Add support for "zone" directly to the netifd so:
> 1. It works for all protocols
> 2. Handlers don't have to duplicate code
> 
> Signed-off-by: Rafał Miłecki <rafal at milecki.pl>
Good idea! I think once this is merged, we should also change the 
default network/firewall config to make use of this and reference zones 
from interfaces instead of the other way around.

- Felix