Add support for relayer EIP-7702 authorizations

[patrislav]

Usage:

signedTxns, err := w.SignTransactions(ctx, sequence.Transactions{txn})
if err != nil { /* ... */ }

authNonce, err := w.GetProvider().PendingNonceAt(ctx, w.Address())
if err != nil { /* ... */ }

auth, err := gethTypes.SignSetCode(w.privateKey, gethTypes.SetCodeAuthorization{
	ChainID: *uint256.NewInt(chainID),
	Address: common.HexToAddress(eip7702Implementation),
	Nonce:   authNonce,
})
if err != nil { /* ... */ }

signedTxns.Authorization = &auth

w.SendTransactions(ctx, signedTxns)