move help to global commands

Help is show in each command flags and no-color is in global section. I
was thinking whether to move no-color in each command flags or help to
global.
When help is in global other useful command flags are seems nicely
grouped.

cli/cmd/root.go

@@ -18,6 +18,8 @@ func Execute(ctx context.Context, version string) error {
 	}
 	// no-color is handled in cli/log pacakge
 	cmd.PersistentFlags().Bool("no-color", false, "don't use colors in output")
+	cmd.PersistentFlags().Bool("help", false, "show command help") // move help to global commands
+	cmd.Flags().Bool("version", false, "show mantil version")      // remove -v shortcut for version
 
 	add := func(factory func() *cobra.Command) {
 		sub := factory()