Extend ethclient test, implement new TxID spec

- Implement new TxID spec that distinguishes L1UserTx and L1CoordinatorTx
- Replace some type []*Foo by []Foo
- Fix HistoryDB & L2DB bug: in case of error, a rollback was applied and the returned error was nil
- Reorder inserts in historydb.NewHistoryDB() to follow foreign key dependencies
- Add initial synchronizer test with test.Client (for now, only tested l1UserTxs, blocks, addToken)
- Update L1UserTx event in test.Client

common/tx.go

@@ -12,6 +12,11 @@ import (
 )
 
 const (
+	// TXIDPrefixL1UserTx is the prefix that determines that the TxID is
+	// for a L1UserTx
+	//nolinter:gomnd
+	TxIDPrefixL1UserTx = byte(0)
+
 	// TXIDPrefixL1CoordTx is the prefix that determines that the TxID is
 	// for a L1CoordinatorTx
 	//nolinter:gomnd