silx.gui.plot.ImageView: Fixed profile window, added setProfileWindowBehavior method

[t20100]

This PR:

• restores previous behavior for displaying profile windows (i.e., pop-up)
• adds ImageView.get|setProfileWindowBehavior method to change it to embed horizontal, vertical and cross profiles on the side widgets.
• adds ImageView.getProfileToolBar and deprecates ImageView.profile attribute.

closes #3454

[woutdenolf]

• API looks good.
• I cannot judge what additional things need to be done when swapping toolbars.
• Implementation: perhaps make it clear that "popup" is the default by changing

class ImageView(PlotWindow):
    def __init__(self, parent=None, backend=None):
        self.__profile = ProfileToolBar(plot=self)
        self.addToolBar(self.__profile)

to this

class ImageView(PlotWindow):
    def __init__(self, parent=None, backend=None):
        self.__profile = None
        self.setProfileWindowBehavior('popup')

class ImageViewMainWindow(ImageView):
    def __init__(self, parent=None, backend=None):
           self.__profileMenu = None
    
    def __updateProfileMenu(self):
        if self.__profileMenu is None:
            self.__profileMenu = self.menuBar().addMenu('Profile')

Or something like that? Up to you.

[woutdenolf]

@t20100 I'm still bothered by this toolbar swapping. Would it be possible to have the behavior option in silx.gui.plot.profile._CustomProfileManager so that we don't need a silx.gui.plot.imageview._CustomProfileManager and silx.gui.plot.imageview._ProfileToolBar?

[t20100]

@woutdenolf you're right, even if to me you only want to call setProfileWindowBehavior when creating the widget, but you never know...

Last commit moves the switch of behavior to the silx.gui.plot.ImageView._CustomProfileManager.
The "embedded" behavior is specific to ImageView so to me it cannot really go as is into silx.gui.plot.profile._CustomProfileManager (I can give it a try though).

[t20100]

Should be fine now: no longer need for silx.gui.plot.imageview._CustomProfileManager and silx.gui.plot.imageview._ProfileToolBar.

[woutdenolf]

Thanks @t20100 it's better:

• no swapping of toolbars
• no extra toolbar and manager classes in ImageView.py
• explicit default behavior

LGTM