feat(dnf): fix dnf5 addRepo compatibility, expand test coverage

- Fix addRepo to use 'config-manager addrepo --from-repofile=' for dnf5
  (dnf4 uses 'config-manager --add-repo')
- Add fedora:latest (dnf5) to containertest matrix
- Add IsDNF5 detection integration test
- Add RepoManager and NameNormalizer integration test coverage
- Rename containertest fedora entry to fedora-dnf4 for clarity

integration_test.go

@@ -57,11 +57,17 @@ var distros = []distroTest{
 		packages: "./pacman/ ./detect/",
 	},
 	{
-		name:     "fedora-dnf",
+		name:     "fedora-dnf4",
 		image:    "fedora:39",
 		setup:    installGo("dnf install -y tree sudo wget"),
 		packages: "./dnf/ ./rpm/ ./detect/",
 	},
+	{
+		name:     "fedora-dnf5",
+		image:    "fedora:latest",
+		setup:    installGo("dnf install -y tree sudo wget"),
+		packages: "./dnf/ ./rpm/ ./detect/",
+	},
 }
 
 func TestContainers(t *testing.T) {