Widen the signature of invert_birational_map

[simonbrandhorst]

Quoting @wdecker : "The Singular counterpart of the OSCAR function invert_birational_map does not only work for curves. As we now have also higher-dimensional varieties , it might make sense to also allow more general type signatures."

[fieker]

Can be solved quick and dirty or slow and thorough... So far no volounteers for either @wdecker , @jankoboehm