CLOUDSTACK-5221:
In order to keep backward compatibility, listisos should return an empty response than an error when id of a removed iso is passed.
CLOUDSTACK-4793: UI > Virtual Routers > Select View > add "group by pod".
CLOUDSTACK-4793: UI > Virtual Routers > Select View > add "group by cluster".
CLOUDSTACK-4793: UI > Virtual Routers > Select View > group by cluster > detailView > add pod name, zone name.