kubectl-plugin: add page (#20311)

Signed-off-by: Emmanuel Ferdman <emmanuelferdman@gmail.com>
Co-authored-by: Sebastiaan Speck <12570668+sebastiaanspeck@users.noreply.github.com>
Co-authored-by: Meinard Francisco <44516102+znarfm@users.noreply.github.com>

pages/common/kubectl-plugin.md

@@ -0,0 +1,16 @@
+# kubectl plugin
+
+> Manage kubectl plugins that extend the functionality of the command.
+> More information: <https://kubernetes.io/docs/reference/kubectl/generated/kubectl_plugin/>.
+
+- List all available plugins on the system `$PATH`:
+
+`kubectl plugin list`
+
+- List only the executable names of available plugins without full paths:
+
+`kubectl plugin list --name-only`
+
+- Display help:
+
+`kubectl plugin {{[-h|--help]}}`