CLLI and MCVD chunks cannot be set with C++ api

[therahedwig]

I'm currently working on handling static HDR Metadata in Krita. Libheif has support for these, in the regular API, but Krita is using the C++ api. And while I can read the data with some effort, writing it to heif and avif files is really clunky.

[farindk]

Yes, the C++ interface does not get the love it deserves. It is quite outdated.
I think this needs a bigger update. Probably moving to a new, more modern C++ interface, using std::expected for error handling and the header file split into separate files per class.