Add ListAliases call

[GeorgeTsagk]

Description

This PR exposes LND's ListAliases RPC call as part of the LightningClient interface

[guggero]

Ah, need to add the permissions for /lnrpc.Lightning/ListAliases to the testdata/permissions.json:

        "/lnrpc.Lightning/ListAliases": {
            "permissions": [
                {
                    "entity": "offchain",
                    "action": "read"
                }
            ]
        },

[bhandras]

LGTM 🎉