You are looking for the plugins in your Downloads folder. On the ionic pro server this folder will not be there. I would suggest creating a folder at the root of your project and putting your plugins in there (only the ones you need).
ex:
{root of your project}/externals/good/
you can then add your plugins like this
cordova plugin add externals/good/{plugin-name}
(you can change externals/good however you like)
I’m not sure this will work though as you also need the BlackBerry Dynamics iOS SDK installed on the machine to build the app which I don’t think will be available on the Ionic Pro server. You probably will have to build your app with your own machine.
Hope that helps