RFE: provide C bindings for libpkgmanifest

[fpoirotte]

Hello,

I would like to use libpkgmanifest with other package managers beside dnf4/5.
In my case, I would like to target apk.
apk is written in pure C, so I would need C bindings to interact with libpkgmanifest.

I have a PR (created using GitHub Copilot / Claude Opus 4.6) ready for this, if this is something you are willing to consider.

Best regards,
François