Make InfoWindowAdapter dynamically updateable

[ivovandongen]

Analog to #5237.

Add the possibility to invalidate the InfoWindowAdapter so that the content is refreshed on the map. As the InfoWindowAdapter is an interface and we don't want to break the api, the easiest way to provide this would probably be add an abstract class extending InfoWindowAdapter with an invalidate() method that may be called so that the infowindow contents is refreshed.

[ivovandongen]

Added an example on how to dynamically update the InfoWindow contents on some trigger (map clicks in this example).

Did have to change up the placement update code on InfoWindow a bit. All-in-all, I think this needs a bit of an overhaul as there are already too many exceptions in there and it's not really meant for updating (only initial placement).

[tobrun]

This was merged with 4.1.0 release branch in #5375, adding milestone and closing.