* add Makefile that adds Device.Firewall. and Device.NAT. tr181
data model objects as a micro service
* add CONFIG_FIREWALLMNGR_PORT_TRIGGER option, which, when enabled
includes support for Device.NAT.PortTrigger. object and selects
appropriate kmod dependencies, and is enabled by default
* copy port-trigger scripts to firewallmngr, as it might be
archived in future
