Implement imageBounds to make image layers usable

[krabina]

With the mage layers option of leaflet SMW quieris is working in general, I could not find a way to set an image to the correct size or align it somehow so that coordinates make sense.

See this example: https://maps.extension.wiki/wiki/User:Krabina/ImageLayers while this is a silly example, image the image being a historical map of Berlin, where actual coordinates would make sense. However, the coordinates displayed to seem to "think" that a world map is shown.

In the leaflet documentation, I found the hint of the imageBounds parameter: https://leafletjs.com/reference-1.7.1.html#imageoverlay I guess if this is implemented then there would be an option to align actual coordinates with an image.

In case anyone has better hints on how to make this usable, please feel free to discuss this here.