Add forfeit address in GetInfo (#326)

* keep track of forfeit transaction funds

* [btc-embedded] use p2wpkh address

* [sdk] fix clients

* use script as argument of BuildForfeitTxs

api-spec/openapi/swagger/ark/v1/service.swagger.json

@@ -631,6 +631,9 @@
         },
         "boardingDescriptorTemplate": {
           "type": "string"
+        },
+        "forfeitAddress": {
+          "type": "string"
         }
       }
     },