Add Lightning Network

[tiero]

The ideal high-level flow should be the same as the liquid one, passing the optional flag -ln or --lightning

Being the network regtest where we are focusing on, we need at least two different wallets in order to open channels and use for local development. We can use both c-lightning and lnd so in this way we can cross-test the two main implementations.

[tiero]

We think https://github.com/jamaljsr/polar does a great job to have a local docker box for lighting so we are going to close this. Thanks so much, @ldub for the initial effort.