Add abstraction method of processTxs to StateDB

- Update GHA lint.yml increasing timeout time to avoid GHA Lint errors
- Update common.BatchNum & common.Idx & common.Nonce usage in StateDB
- Add abstraction method of processTxs to StateDB
    - Which will be used by Synchronizer & BatchBuilder

common/tx.go

@@ -2,6 +2,7 @@ package common
 
 import (
 	"encoding/binary"
+	"fmt"
 	"math/big"
 )
 
@@ -20,6 +21,15 @@ func (idx Idx) BigInt() *big.Int {
 	return big.NewInt(int64(idx))
 }
 
+// IdxFromBytes returns Idx from a byte array
+func IdxFromBytes(b []byte) (Idx, error) {
+	if len(b) != 4 {
+		return 0, fmt.Errorf("can not parse Idx, bytes len %d, expected 4", len(b))
+	}
+	idx := binary.LittleEndian.Uint32(b[:4])
+	return Idx(idx), nil
+}
+
 // IdxFromBigInt converts a *big.Int to Idx type
 func IdxFromBigInt(b *big.Int) (Idx, error) {
 	if b.Int64() > 0xffffffff { // 2**32-1
@@ -64,7 +74,6 @@ type Tx struct {
 	TxID     TxID
 	FromIdx  Idx // FromIdx is used by L1Tx/Deposit to indicate the Idx receiver of the L1Tx.LoadAmount (deposit)
 	ToIdx    Idx // ToIdx is ignored in L1Tx/Deposit, but used in the L1Tx/DepositTransfer
-	TokenID  TokenID
 	Amount   *big.Int
 	Nonce    Nonce // effective 40 bits used
 	Fee      FeeSelector