global-functions: $DeviceInfo: show license level if available

This now shows license level for CHR.

The property is named different for Routerboards. As these have the
license bundled to hardware anyway we do not show it there.

global-functions

@@ -201,6 +201,7 @@
   :do {
     :set RouterBoard [ / system routerboard get ];
   } on-error={ }
+  :local License [ / system license get ];
   :local Update [ / system package update get ];
 
   :return ( \
@@ -212,6 +213,8 @@
          [ $IfThenElse ([ :len ($RouterBoard->"revision") ] > 0) \
            (" " . $RouterBoard->"revision") ] . \
        "\nSerial number:  " . $RouterBoard->"serial-number") ] . \
+    [ $IfThenElse ([ :len ($License->"level") ] > 0) \
+       ("\nLicense:        " . $License->"level") ] . \
        "\nRouterOS:" . \
        "\n    Channel:    " . $Update->"channel" . \
        "\n    Installed:  " . $Update->"installed-version" . \