feat(ci): add ujust recipe to list installed rpms

[ledif]

I find myself relearning how to list the packages installed on the currently booted image so I figured that this could be handy to include by default.

I am also adding a GitHub action to validate justfiles.

❯❯ ujust list-installed-rpms
ostree commit: ebfe7b05027baa70709a82208b18684622f72b5e7a90fbdf7130770ca5f720a6
 ImageMagick-1:7.1.1.41-1.fc41.x86_64
 ImageMagick-libs-1:7.1.1.41-1.fc41.x86_64
 Judy-1.0.5-37.fc41.x86_64
 LibRaw-0.21.3-1.fc41.x86_64
 ModemManager-1.22.0-4.fc41.x86_64
 ModemManager-glib-1.22.0-4.fc41.x86_64
 NetworkManager-1:1.50.0-1.fc41.x86_64
 NetworkManager-bluetooth-1:1.50.0-1.fc41.x86_64
 NetworkManager-config-connectivity-fedora-1:1.50.0-1.fc41.noarch
 NetworkManager-libnm-1:1.50.0-1.fc41.x86_64
 NetworkManager-openconnect-1.2.10-6.fc41.x86_64
 NetworkManager-openvpn-1:1.12.0-2.fc41.x86_64
 NetworkManager-ppp-1:1.50.0-1.fc41.x86_64
 NetworkManager-team-1:1.50.0-1.fc41.x86_64
 NetworkManager-vpnc-1:1.2.8-8.fc41.x86_64
 NetworkManager-wifi-1:1.50.0-1.fc41.x86_64
 NetworkManager-wwan-1:1.50.0-1.fc41.x86_64
 PackageKit-Qt6-1.1.1-6.fc41.x86_64
 PackageKit-glib-1.2.8-8.fc41.x86_64
 SDL2-2.30.11-1.fc41.x86_64
 SDL2_image-2.8.4-1.fc41.x86_64
 SDL2_ttf-2.22.0-3.fc41.x86_64
 SLOF-20220719-5.git6b6c16b4.fc41.noarch
 aardvark-dns-2:1.13.1-1.fc41.x86_64
 abattis-cantarell-fonts-0.301-13.fc41.noarch
 abattis-cantarell-vf-fonts-0.301-13.fc41.noarch
 accounts-qml-module-qt6-0.7^20231216.05e79eb-4.fc41.x86_64
 accountsservice-23.13.9-5.fc41.x86_64

[ ... snip ... ]

 zlib-ng-compat-devel-2.2.3-1.fc41.x86_64
 zram-generator-1.1.2-12.fc41.x86_64
 zram-generator-defaults-1.1.2-12.fc41.noarch
 zsh-5.9-15.fc41.x86_64
 zstd-1.5.6-2.fc41.x86_64
 zvbi-0.2.42-1.fc41.x86_64
 zxing-cpp-2.2.1-2.fc41.x86_64

[inffy]

nice and handy! lgtm