Faire fonctionner le serveur avec de vrais nodes

Implementation à supporter
- [LND](https://lightning.engineering/api-docs/api/lnd/index.html)
- [Éclair](https://acinq.github.io/eclair/#introduction)

LND est prioritaire vu que c'est l'implémentation la plus populaire.

Si tout ce passe bien [Core Lightning](https://lightning.readthedocs.io/) sera la dernière cible.

Start by reading the LND API documentation linked in the issue, since LND is the stated priority, then compare the Eclair and Core Lightning API documentation. Done means the server supports real nodes, beginning with LND and eventually covering the other listed implementations.

Written by the indexing model from the issue text.