refactor: Move transaction_identifier.h to primitives

Moves the file from `src/util` to `src/primitives`. Now that the
refactor is complete, Txid and Wtxid are fundamental types, so it
makes sense for them to reside in `src/primitives`.

src/qt/sendcoinsdialog.h

@@ -5,9 +5,9 @@
 #ifndef BITCOIN_QT_SENDCOINSDIALOG_H
 #define BITCOIN_QT_SENDCOINSDIALOG_H
 
+#include <primitives/transaction_identifier.h>
 #include <qt/clientmodel.h>
 #include <qt/walletmodel.h>
-#include <util/transaction_identifier.h>
 
 #include <QDialog>
 #include <QMessageBox>

src/qt/transactionrecord.h

@@ -6,8 +6,8 @@
 #define BITCOIN_QT_TRANSACTIONRECORD_H
 
 #include <consensus/amount.h>
+#include <primitives/transaction_identifier.h>
 #include <uint256.h>
-#include <util/transaction_identifier.h>
 
 #include <QList>
 #include <QString>

src/qt/transactionview.h

@@ -7,8 +7,8 @@
 
 #include <qt/guiutil.h>
 
+#include <primitives/transaction_identifier.h>
 #include <uint256.h>
-#include <util/transaction_identifier.h>
 
 #include <QWidget>
 #include <QKeyEvent>

src/qt/walletmodel.h

@@ -10,8 +10,8 @@
 #include <qt/walletmodeltransaction.h>
 
 #include <interfaces/wallet.h>
+#include <primitives/transaction_identifier.h>
 #include <support/allocators/secure.h>
-#include <util/transaction_identifier.h>
 
 #include <vector>