Fedora 44: replace dnf4 %post with dnf5 repo override

The %post scriptlet ran "dnf config-manager --save --setopt=...", which
is dnf4-only syntax. On Fedora 44 (dnf5) it fails with "Unknown argument
--save" (exit 2), so every install of this package ends with the dnf
transaction marked as an error even though the package is installed, and
the fedora*/updates* excludepkgs were never applied.

Drop the scriptlet and ship a declarative dnf5 distribution override at
/usr/share/dnf5/repos.override.d/50-ims-fedora-extras.repo instead. It
uses glob repo IDs ([fedora*], [updates*]) to set
excludepkgs=freeipa* frr* strongswan* on the stock Fedora repos.

Require dnf5 explicitly.

50-ims-fedora-extras.repo

@@ -0,0 +1,9 @@
+# InfoMaOS: exclude packages that are rebuilt in ims-fedora-extras from the
+# stock Fedora repositories. Loaded by dnf5 as a distribution repo override
+# (see "DROP-IN REPO DIRECTORIES" in dnf5.conf(5)).
+
+[fedora*]
+excludepkgs=freeipa* frr* strongswan*
+
+[updates*]
+excludepkgs=freeipa* frr* strongswan*