DSA: via netifd

Tried getting some simple configurations working on a mamba with the stanza syntax as per ML, which I understand is ready to be kicked around. Could not make anything I tried work (but the mamba can be interesting), wondering if anyone else has taken a stab. I see that nbd has another patch series in the pipe, perhaps that is needed, but needs refreshing to be applied.

There was a syntax change as per commit, but it seems that with push, something as simple as:

config device switch0
	option name 'switch0'
	option type bridge

config bridge-vlan
	option device 'switch0'
	option vlan '1'
	option ports "lan1 lan2 lan3 lan4"

should setup correctly.