stop using deprecated apt-key in Qubes builder (qubes-builder-debian) (prevents removal from gnupg from Debian minimal templates)

[adrelanos]

Qubes OS release

R4.3

Brief summary

apt-key is deprecated by upstream, Debian. Quote https://manpages.debian.org/bookworm/apt/apt-key.8.en.html

apt-key - Deprecated APT key management utility

apt-key is no longer required.

This caused the issue of gnupg not being removable from Debian minimal template. This is because deprecated apt-key makes internally use of gpg, has a undeclared dependency on gnupg.

• Remove packages which are already called by other qubes dependencies qubes-builder-debian#85
• (Re)move Debian packages in packages.list and packages_minimal.list #6566

Steps to reproduce

See qubes-builder-debian uses apt-key code search https://github.com/search?q=repo%3AQubesOS%2Fqubes-builder-debian%20apt-key&type=code for evidence.

Expected behavior

Qubes builder not using deprecated tools such as apt-key.

Actual behavior

Qubes builder using apt-key.

Additional information

apt-key is no longer required. There is no need to perform any gpg format conversion anymore.

/usr/share/keyrings folder nowadays supports:

• A) gpg binary format (`.gpg); and,
• B) gpg --armored format (.asc).

Just place the key there. Using B) preferably.