webadmin: Add cluster policy to edit cluster

Added the ability to set the cluster policy in the create/edit cluster
popup view

The original ClusterPolicyPopupView was dropped and the link from the
original button was changed to the ClusterPopupView

Change-Id: I195d9ec1c7901a31e6e656221964d82bc90c9695
Signed-off-by: Ofri Masad <omasad@redhat.com>