Add Batch feature (XLS-56) (#5060)

- Specification: [XRPLF/XRPL-Standards 56](https://github.com/XRPLF/XRPL-Standards/blob/master/XLS-0056d-batch/README.md)
- Amendment: `Batch`
- Implements execution of multiple transactions within a single batch transaction with four execution modes: `tfAllOrNothing`, `tfOnlyOne`, `tfUntilFailure`, and `tfIndependent`.
- Enables atomic multi-party transactions where multiple accounts can participate in a single batch, with up to 8 inner transactions and 8 batch signers per batch transaction.
- Inner transactions use `tfInnerBatchTxn` flag with zero fees, no signature, and empty signing public key.
- Inner transactions are applied after the outer batch succeeds via the `applyBatchTransactions` function in apply.cpp.
- Network layer prevents relay of transactions with `tfInnerBatchTxn` flag - each peer applies inner transactions locally from the batch.
- Batch transactions are excluded from AccountDelegate permissions but inner transactions retain full delegation support.
- Metadata includes `ParentBatchID` linking inner transactions to their containing batch for traceability and auditing.
- Extended STTx with batch-specific signature verification methods and added protocol structures (`sfRawTransactions`, `sfBatchSigners`).

src/test/jtx/impl/multisign.cpp

@@ -65,17 +65,6 @@ signers(Account const& account, none_t)
 
 //------------------------------------------------------------------------------
 
-msig::msig(std::vector<msig::Reg> signers_) : signers(std::move(signers_))
-{
-    // Signatures must be applied in sorted order.
-    std::sort(
-        signers.begin(),
-        signers.end(),
-        [](msig::Reg const& lhs, msig::Reg const& rhs) {
-            return lhs.acct.id() < rhs.acct.id();
-        });
-}
-
 void
 msig::operator()(Env& env, JTx& jt) const
 {