Runner: Support an image collage

[alexander-nitsche]

Support a collage of DOM elements with current relative positions or custom positions, e.g. to print only an expanded context menu like here:

[linawolf]

Could we maybe solve this in Rst with image series? https://typo3-documentation.github.io/sphinx_typo3_theme_rendering_test/ImagesAndFigures/Index.html#images-of-series-a