{yum, dnf}-config-manager: add page (#14061)

Co-authored-by: Managor <42655600+Managor@users.noreply.github.com>
Co-authored-by: Sebastiaan Speck <12570668+sebastiaanspeck@users.noreply.github.com>

pages/linux/dnf-config-manager.md

@@ -0,0 +1,28 @@
+# dnf config-manager
+
+> Manage DNF configuration options and repositories on Fedora-based systems.
+> More information: <https://manned.org/dnf-config-manager>.
+
+- Add (and enable) a repository from a URL:
+
+`dnf config-manager --add-repo={{repository_url}}`
+
+- Print current configuration values:
+
+`dnf config-manager --dump`
+
+- Enable a specific repository:
+
+`dnf config-manager --set-enabled {{repository_id}}`
+
+- Disable specified repositories:
+
+`dnf config-manager --set-disabled {{repository_id1 repository_id2 ...}}`
+
+- Set a configuration option for a repository:
+
+`dnf config-manager --setopt={{option}}={{value}}`
+
+- Display help:
+
+`dnf config-manager --help-cmd`