Add a way to print a message per Component and Host

[frlan]

There are scenarios, where in libraries like batou_ext the default behaviour will change in future. A common way of doing it is to print a message informing a user about it.

Something like

class MyComponent(Component):
    def configure(self):
        self.log("Warning: Will be changed") 

might do the trick, but having a deployment with a big number of hosts it might get's quiet noisy.

It would be cool to have a build-in way to print one message only for the hosts the component actually is activated on only one time.