[Pagebuilder] Make Imageblocks localizable

[Algorithman]

Is your feature request related to a problem? Please describe.
What do I mean with that?
Sometimes images have special fonts/colored fonts or other text which is placed at specific spots.
To do this with multiple blocks (or with an image as background in a text block) is possible, but for sure quite difficult.
A localizable image (separate images for each language) in the picture block would solve this problem.

[stefanmuellerdo]

Localised images in Media Manager would be a great feature for webstores with an international audience.

#811 is related to this in terms of SEO aspects (for media filenames)