luci-mod-network: add support for bonding device in netifd

netifd support for bonding devices has been added in commit 5ba9744,
 the other way to have bonding available in luci was via the luci-proto-bonding
 a and its proto-bonding dependency.

This method forces to have an IP address on a bond interface
 due to a netifd limitation. This can causes some issues if you want
 to bridge an ethernet port and a bond.

This patch aim to have the proto device to be configurable not
 as an interface protocol but as a device.

Signed-off-by: hitech95 <[email protected]>