Add support for exif and other metadata in heic files

[albertogasparin]

Libheif has a bunch of methods like heif_context_add_exif_metadata that allows to store/preserve exif metadata.
It would be great if we could add a parameter to encodeHeic to allow passing that data and save it into the file

[awxkee]

You could use https://github.com/Ashampoo/kim for that. This is easier and safer way to work with untrusted data.

[albertogasparin]

I wouldn’t mind leveraging another lib to create the exif data payload, but it seems like also that library does not support writing exif data on heif files.
It seems like libheif is the only implementation that I could find that can add exif data, but it does so on creation.