New address encoding (#356)

* [common] rework address encoding

* new address encoding

* replace offchain address by vtxo output key in DB

* merge migrations files into init one

* fix txbuilder fixtures

* fix transaction events

server/internal/core/domain/payment.go

@@ -68,9 +68,12 @@ func (p Payment) validate(ignoreOuts bool) error {
 		return fmt.Errorf("missing outputs")
 	}
 	for _, r := range p.Receivers {
-		if len(r.OnchainAddress) <= 0 && len(r.Descriptor) <= 0 {
+		if len(r.OnchainAddress) <= 0 && len(r.Pubkey) <= 0 {
 			return fmt.Errorf("missing receiver destination")
 		}
+		if r.Amount == 0 {
+			return fmt.Errorf("missing receiver amount")
+		}
 	}
 	return nil
 }
@@ -80,6 +83,10 @@ type VtxoKey struct {
 	VOut uint32
 }
 
+func (k VtxoKey) String() string {
+	return fmt.Sprintf("%s:%d", k.Txid, k.VOut)
+}
+
 func (k VtxoKey) Hash() string {
 	calcHash := func(buf []byte, hasher hash.Hash) []byte {
 		_, _ = hasher.Write(buf)
@@ -96,9 +103,9 @@ func (k VtxoKey) Hash() string {
 }
 
 type Receiver struct {
-	Descriptor     string
 	Amount         uint64
-	OnchainAddress string
+	OnchainAddress string // onchain
+	Pubkey         string // offchain
 }
 
 func (r Receiver) IsOnchain() bool {
@@ -107,7 +114,8 @@ func (r Receiver) IsOnchain() bool {
 
 type Vtxo struct {
 	VtxoKey
-	Receiver
+	Amount    uint64
+	Pubkey    string
 	RoundTxid string
 	SpentBy   string // round txid or async redeem txid
 	Spent     bool