Add some features to QAction an QMenu

I suggest to add some features to QMenu and QAction:

1)  create a signal to intercept a right click on a QAction, to be able to do this for example:

connect(action, SIGNAL(right_clicked()), this, SLOT(doSomething()));

2) Actually we are able to do set a context menu on a widget but not on an action. My suggestion is to make possible to set a context menu policy on an action. Actually we can do this :

myWidget->setContextMenuPolicy(Qt::CustomContextMenu);

connect(myWidget, SIGNAL(customContextMenuRequested(const QPoint&)), this, SLOT(ShowContextMenu(const QPoint&)));

but not this below. And my suggestion to be able to do ths:

myAction->setContextMenuPolicy(Qt::CustomContextMenu);

connect(myAction, SIGNAL(customContextMenuRequested(const QPoint&)), this, SLOT(ShowContextMenu(const QPoint&)));

3) Make possible to hide the right arrow/triangle on a QMenu. The only possibility to hide it today is to make it 0x0 px size with stylesheets: this problem is discussed in many forums like this one: https://forum.qt.io/topic/35113/how-to-hide-the-right-arrow-in-qmenu/6

4) Actually giving a pointer of an action as a parent to a QMenu raise an exceptin at the execution, for example doing this:

QAction* action= new QAction("foo", this);

QMenu* menu = new QMenu((QWidget*) action);

raises an exception. My goal was to get the "father" of the menu in the arborescence, since I made this: 

action->setMenu(menu);

and once the menu open I was not able to know to which action set this menu. There is no function menu->getLinkedAction() or soething like that. So I tried to make this instead:

QAction* act= new QAction("foo", this);

QMenu* alpha = new QMenu((QWidget*) act);

act->setMenu(alpha);

....

//At the slot that manage the context menu "alpha" I wasn't able to this: 

QAction* act2 = alpha->parent();

because of the excepetion raised at "QMenu* alpha = new QMenu((QWidget*) act);"

My suggestion is to search for solution to make the ability to get the "father" of this QMenu