Add NAT-PMP/UPnP option as default on Umbrel Lightning

[ffrediani]

Many nodes running on standard broadband connections make usage of dynamic IP address which is not a problem as long it is advertised correctly in order that other nodes can reach back. To facilitate this LND has the configuration nat=true

It fetch a node's external IP address using built-in techniques and make a request to the local router to forward the necessary port to the node making it reachable on Clearnet and thus improving node connectivity avoiding it to depend entirely on Tor network which is slower and may have trouble to route payments.

Having this option enabled by default on Umbrel Lightning makes it very handy to most users that doesn't need to worry about manual port forward.

If for some reason not desirable to make it default at least make it an option in the Web Interface to allow users easily turn it on when desired.

Reference: https://docs.lightning.engineering/lightning-network-tools/lnd/nat_traversal
Obs: In order to enable this it is important to make sure the system-specific binaries in order to detect your gateway device's address are present as it mentions on the documentation.