Allow additional styling for elements in markdown
beispielsweise Bilder zentrieren: https://stackoverflow.com/questions/3912694/using-markdown-how-do-i-center-an-image-and-its-caption/43691451
beispielsweise Bilder zentrieren: https://stackoverflow.com/questions/3912694/using-markdown-how-do-i-center-an-image-and-its-caption/43691451