util: move error.h TransactionError enum to node/types.h

New node/types.h file is analagous to existing wallet/types.h and is a better
place to define simple node types that are shared externally with wallet and
gui code than the util library.

Motivation for this change is to completely remove util/error.h file currently
holding TransactionError in a followup commit.

src/node/types.h

@@ -0,0 +1,33 @@
+// Copyright (c) 2010-2021 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+//! @file node/types.h is a home for public enum and struct type definitions
+//! that are used by internally by node code, but also used externally by wallet
+//! or GUI code.
+//!
+//! This file is intended to define only simple types that do not have external
+//! dependencies. More complicated types should be defined in dedicated header
+//! files.
+
+#ifndef BITCOIN_NODE_TYPES_H
+#define BITCOIN_NODE_TYPES_H
+
+enum class TransactionError {
+    OK, //!< No error
+    MISSING_INPUTS,
+    ALREADY_IN_CHAIN,
+    P2P_DISABLED,
+    MEMPOOL_REJECTED,
+    MEMPOOL_ERROR,
+    INVALID_PSBT,
+    PSBT_MISMATCH,
+    SIGHASH_MISMATCH,
+    MAX_FEE_EXCEEDED,
+    MAX_BURN_EXCEEDED,
+    EXTERNAL_SIGNER_NOT_FOUND,
+    EXTERNAL_SIGNER_FAILED,
+    INVALID_PACKAGE,
+};
+
+#endif // BITCOIN_NODE_TYPES_H