Bug 2209387

(I'm filing issues with all the packages that currently depend on `dnf`.)

DNF 5 is a new package manager that will replace DNF 4 in Fedora 39+. Starting in Fedora 39, the `dnf` command will be owned by the `dnf5` package rather than the `dnf` package, and `dnf5` will obsolete `dnf`. Since libdnf-plugin-subscription-manager currently depends on `dnf`, it should choose one of the following strategies to avoid breaking the approaching Fedora upgrade and maintain compatibility with future versions of Fedora:
- Add support for DNF 5 and depend on the `libdnf5` or `dnf5` package in Fedora 39+ instead of `dnf`. Builds of DNF 5 are available in this COPR repository: https://copr.fedorainfracloud.org/coprs/rpmsoftwaremanagement/dnf5-unstable/, and documentation is available here: https://dnf5.readthedocs.io/en/latest/.
- Alternatively, or in the meantime, change the libdnf-plugin-subscription-manager package to depend on `python3-dnf` instead of `dnf`. The Python API and /usr/bin/dnf-3 have always been provided by `python3-dnf`, while `dnf` provides the symlink from /usr/bin/dnf to /usr/bin/dnf-3. Once `dnf` is obsoleted, the old DNF 4 command will still be available in the distribution, but only as `dnf-3`. (The binary is called `dnf-3`  rather than `dnf4` for historical reasons; it was originally the Python 3 version of DNF).

libdnf-plugin-subscription-manager should eventually be rewritten as a DNF 5 plugin, but the immediate issue is dropping the dependency on `dnf`. We are planning to replace DNF with DNF 5 in Fedora Rawhide very soon, in the next couple weeks, and the `libdnf-plugin-subscription-manager` package will break as long as it still depends on the `dnf` package.

For more information about the switch to DNF 5, see https://fedoraproject.org/wiki/Changes/ReplaceDnfWithDnf5.

Reproducible: Always