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

pkg/client-sdk/client/client.go

@@ -61,6 +61,7 @@ type Info struct {
 	Network                    string
 	Dust                       uint64
 	BoardingDescriptorTemplate string
+	ForfeitAddress             string
 }
 
 type RoundEventChannel struct {