Undeprecate `poppler_document_new_from_data` and fix its API.
Poppler is not used only from C, when using poppler from C++ or rust, the memory is mostly managed indirectly via containers. Passing data from a C++ container is now very cumbersome. This on top also applies to data from a memory mapped file. Therefore, I propose to undeprecate it and to fix its API to something like this:
PopplerDocument *
poppler_document_new_from_data (const char *data,
ptrdiff_t length,
const char *password,
GError **error);