My packages needs to add a key to apts keyring. How?

[Goswin von Brederlow <goswin-v-b@web.de>]

Hi,

I have a package that creates a local repository of packages. For that
to be usable the archives signing key needs to be added to apts
keyring.

I remember that someone was working on support for a keyring directory
like /etc/apt/keyring.d/ where keys could be droped into. Is that
still being pursued? Or is that possible now alraedy?

Lacking that is it OK for a package to call apt-key add from postinst
and apt-key del from prerm?

MfG
        Goswin