Merge #13961: util: Replace boost::signals2 with std::function

ddddce0e46 util: Replace boost::signals2 with std::function (MarcoFalke)

Pull request description:

  This removes the `#include <boost/signals2/signal.hpp>` from `util.h` (hopefully speeding up the build time and reducing the memory usage further after  #13634)

  The whole translation interface is replaced by a function `G_TRANSLATION_FUN` that is set to nullptr in units that don't need translation. (Thus only set in the gui)

Tree-SHA512: 087c717358bbed8bdb409463e225239d667f1ced381abb10e7cd31a41dcdd2cebe20b43c2ee86f0f8e55d53301f75e963f07421a99a7ff4c0cad2c6a375c5ab1

src/qt/transactiontablemodel.cpp

@@ -16,10 +16,10 @@
 #include <core_io.h>
 #include <interfaces/handler.h>
 #include <interfaces/node.h>
-#include <validation.h>
 #include <sync.h>
 #include <uint256.h>
 #include <util.h>
+#include <validation.h>
 
 #include <QColor>
 #include <QDateTime>
@@ -27,6 +27,8 @@
 #include <QIcon>
 #include <QList>
 
+#include <boost/bind.hpp>
+
 // Amount column is right-aligned it contains numbers
 static int column_alignments[] = {
         Qt::AlignLeft|Qt::AlignVCenter, /* status */