Drop PackageKit

[yselkowitz]

The desktop team wants to drop PackageKit from RHEL 11 and migrate to direct use of dnf5daemon. That leaves cockpit as the only consumer, but it turns it also already supports dnf5daemon, so we just need to do some cleanup.

[yselkowitz]

https://src.fedoraproject.org/rpms/cockpit/pull-request/394 to fix dnf5daemon dependencies.

[yselkowitz]

minimization/content-resolver-input#1547

[yselkowitz]

@martinpitt wrote:

Please hold off on this -- we ported on-demand installs to dnfdaemon, but changing the Software Updates and Apps pages and kpatch integration to support both dnfdaemon and packagekit is a gargantuan task and still in progress: https://issues.redhat.com/browse/COCKPIT-647
We don't yet know whether we'll keep cockpit-packagekit package name which will then depend on dnfdaemon on Fedora/RHEL, or rename the package for Fedora/RHEL 11 (but ugh updates).

Moving to backlog.